15:1 “Fear not, Abram…” – From God’s assurance to Abraham, it is clear that Abraham was deeply worried about something.
The Midrashim and commentators generally explain that when Abraham reflected on the miracle which enabled him to slay the kings, although he was greatly outnumbered, he was concerned that the miracle had been possible only as a reward for his previous righteousness – that he could not expect future divine assistance, and that he would be punished for the men he had slain, some of whom may have been righteous. He was also apprehensive that the successors of the four kings would collect even greater armies than before and stage an attack on him. This time, since all his merit had been used to gain the previous victory, he would be defeated (Midrash). He also feared he would die without children.
“I am your shield..” – I am your shield against punishment, for you will not be punished on account of all these people you have slain (Rashi); I am your shield against your enemies. ‘Just as a shield received all spears and withstands them, so will I stand by you.’ Midrash
‘Your reward is very great.’ – Not only need you not fear punishment, but you need not be concerned about the future, for your reward is very great.
God also assured him that there were no righteous people among those whom Abraham slain; rather than deserving punishment for slaying them, he was worthy of reward for ridding the world of the wicked (Midrash).
The Midrash relates that Abraham entertained even further misgivings. He said to God: ‘Sovereign of the Universe! You made a covenant with Noah not to exterminate his children. Yet, through my meritorious acts my covenant superseded his and I was victorious and exterminated the forces of the four kings. Perhaps another will arise who will accumulate even a greater store of precepts earning a new covenant that will supersede mine.
God therefore reassured him that only to Abraham’s children would He set up shields for the righteous – only to Abraham, but not to Noah, did God promise to be a shield; for there did not arise from Noah even one righteous person (aside from Abraham) whose righteousness could have served to spare his fellowman. Moreover He assured him that there would always be a righteous one in each generation among Abraham’s descendants who would shield his sinful fellowman and atone on their behalf.
15:2 ..that I go childless, ..’ – Abraham feared that he would die childless; therefore God reiterated His assurance that his descendants would be as numerous as the stars of the heaven.
One might ask why Abraham felt such fear in view of God’s earlier promise (13:15-16) of the Land to his descendants who would be as the dust of the earth? Further, why would his belief in this second promise be stronger than his belief in the first?
The explanation is that the righteousness never their righteousness for granted. Abraham saw himself growing old and he was still childless. The first prophesy had not been fulfilled, and he feared that his own sin was the cause, or as the Midrash notes, that he was being punished for having slain people in the war. Hence, the principle that the righteous are never confident in this world, they need constant reassurance that they have not deprived themselves of God’s blessing.
15:3 When Abraham said these things he did not suggest that God would renege on His promise. Rather he was apprehensive that he had committed some offense which had forfeited his claim to the promise; or that he thought that the ‘offspring’ was a relative whom God might be considering as equivalent as Abraham’s own child.
Compare the words of Solomon in Ecclesiastes 2:18-19 who also expressed despair at the fate of one who leaves his estate to heirs whose prudence and wisdom are questionable.
Abraham’s concern continues – And even if You were to grant me a son now, in my old age, he will still be young after my demise and will be susceptible to Eliezer’s maneuverings, and will be at the mercy of the elder servant who will, in effect, be his master.
15:4 Suddenly, the Word of Hashem came forth – Regardless of when your son will be born to you, you need not be apprehensive. Your servant will not be your heir; your own offspring will inherit you.
The implication of God’s promise is that Abrahm will father a son at some time in the future, and that the child will be an adult at Abraham’s death so he will not require a guardian nor be susceptible to any servant. In this way he, and none other, would be assured of being the heir Abarbanel).
15:5 “And He took him outside,” – The Midrashic interpretation is: He took him out of the realm of his constellation. Although you have seen by the constellations that you are not destined to have children, it is true only that Abram will have no son, but Abraham will have a son; Sarai will indeed be childless, but Sarah will bear a son. I will change your names from Abram to Abraham and Sarai to Sarah and your constellation will change!
‘Gaze now toward the heavens’ – The Sages have explained that the verb – gaze – always suggests gazing down from above, thus accounting for their explanation that Abraham was raised up above the stars, and as such he was told to gaze down upon them (Malbim).
As far as the Midrashic astrological interpretation cited by Rashi, Ramban notes that he begot Ishmael while his name was still Abram. How then could the Midrash say that Abram will have no son? The answer that Abraham’s fear, as expressed in verse 3 was that he would not have a son as an heir; God therefore assured him that as ‘Abram’ he would not have a son who would be his heir (Ishmael was not his heir – see 21:12); only as Abraham would he father a son. Additionally, it is possible that the astrological indication concerned Abram and Sarai only as a pair together and Ismael was born of Abram and Hagar.
Note: The commentators generally agree that the comparison of Israel to the stars is not measured by the quantity of stars. God had already compared them to ‘the dust of the earth’ and the dust particles of the earth are more numerous than the stars. Rather God was saying that his every descendant would be measured by quality – as worthy and precious as the stars, each of which is individually counted by God for each star is a separate solar system or mighty force. Isaiah 40:26: “Lift up your eyes on high, and see who has created these things, who brings out their host by number; He calls them by name, by the greatness of His might and the strength of His power; not one of them is missing.’
Had God wished to direct Abraham’s attention to the quantity of the stars, it would not have been necessary to show him the heavens, just as He did not show Abraham the dust when He promised – ‘I will make your seed like the dust of the earth.’ Rather, God showed him the stars as if to say, ‘Your national existence will be like that of the stars.’ Here, on earth, everything we see is an evolving product of God’s ‘cause and effect’ natural law. The stars, however, are still pristine products of God’s hand, unchanged since the day He created them. Hence, God was, in effect, telling him, ‘Abandon your earthly, natural speculations. Your offspring will be like the stars, drawing their sustenance from God, above all natural calculations.
Noting also that elsewhere (13:16, 28:14) God compared Abraham’s offspring to the dust of the earth, while here they are likened to the stars in heaven, the Sages (Megillah 16a) derive an ethical lesson: When we do God’s will, we are above all – like the stars in heaven. However, when we disobey God’s will, we are trampled upon by all – like the dust of the earth.
15:6 “..righteousness.” – Ramban questions – why should faith in God, especially by one as great as Abraham, be considered a virtue? ‘God is not a man that He should lie’ (Numbers 23:19)
We are speaking of a man who, on the basis of his faith, was later prepared to sacrifice his beloved son, and had withstood all trials; how could he not show his faith in a good tiding? Ramban suggests that the subject of the verse is Abraham: He (Abraham) considered it an act of righteousness on the part of God that He would promise him a child unconditionally (in God’s righteousness) and without regard to Abraham’s merit, and the possibility he might sin. The verse says there, that Abraham’s trust in God’s promise was total, for, since it was an act of Divine Righteousness, it was irreversible as in the verse (Isaiah 45:23) “By Myself have I sworn, the word is issued from My mouth in righteousness, and shall not turn back.’
It is found in Tanchuma Masei 7, based on the verse, “God is not a man that He should lie” (Numbers 23:19). When God promises to do good, He does not retract His promise even if the generation is guilty of infractions. However, when He threatens to punish, He does retract if the guilty one repents. He promised Abraham the good tiding: “Gaze now at the heavens and count the starts … so shall your offspring be”, and He has done so, for Moses said to the children of Israel (Deuteronomy 1:10): “Behold, you are this day as the stars of heaven.”
We must never forget that Abraham was the First Believer and thus had no one to look back upon. He established his own precedents; his faith was more difficult to come by than ours – for we are ‘believers, sons of believers’, for our forebears already paved a road of unswerving Faith. It is no wonder then that the Torah emphasizes Abraham’s faith as meritorious and noteworthy.
The Covenant Between the Parts: The Promise of the Land – Verses 7-21
Note: The covenant described in the following verses was made when Abraham was seventy years old; chronologically it preceded the prophetic vision of the above verses which, as pointed out above, occurred when Abraham was seventy-five years old.
That the narrative of the Covenant between the Parts commences with this verse is derived from Tosafos Berachos 7b which cites it as an example that the Torah is not necessarily written in chronological order.
While the commentators will generally assume events are chronologically given, there are frequent exceptions. For example, chapters are sometimes written out of sequence to indicate legal or moral teachings derived from the association of seemingly unrelated concepts or events. Or, a particular topic may be narrated until its completion, before a new one is introduced. For example, the Torah tells of Terach’s death before Abraham’s departure to Canaan, which chronologically, Terach did not die until 60 years later and Noah’s death is recorded in 9:29 although Noah was still alive in the days of Abraham.
15:7 “..give you this land..” – Radak and Sforno interprets this as God saying ‘This decree giving you the Land is not new. I intended it from the time I saved you from Ur Kasdim; it was for this very purpose that I rescued you so that the Land would be an inheritance which you would pass on to your children as a father bequeaths his personal belongings to his heirs.’
15:8 “..’My Lord, Hashem Elohim:..” – The Talmud (Berachos 7b) notes that Abraham was the first man ever to call Him Adon, (Master). The obvious question arises why this verse is cited as the ‘first’ rather than verse 2 where the same Name occurs first. It is in this connection that Tosafos explains that the Covenant Between the Parts (verse 7-21) happened before the vision of verses 1-6. Thus, Abraham’s use of the Name Adonai in this verse is the first in history.
The Name: My Lord Hashem/Elohim
This combination of God’s Names is most unusual, especially the second Name which has the spelling of the Four-Letter Name but the punctuation of Elohim.
According to Mizrachi (Deuteronomy 3:34) whose interpretation we adopt in the translation, the name in our context is the salutation by which Abraham and Moses addressed God, ie., my Lord, for the word means Master, thus the Name is used to indicate complete obedience and acceptance.
The second Name has the spelling of the Four Letter Name but the punctuation of Elohim. It appears in the five books of Moses only four times: Genesis 15:2, 15:8, Deuteronomy 3:24 and 9:26. Although it is found in various books of Prophets, it is used extensively only in Ezekiel. ‘Hashem’ commonly refers to God’s Attribute of Mercy while Elohim alludes to the Attribute of Judgment. According to Mizrachi, this Name, combining mercy with judgment, implies the plea that even in judgment, God should temper his decree with mercy.
“ how shall I know..” – Rashi explains that in addition to the plain meaning that Abraham sought a sign, another interpretation is: By what merit will my descendants sustain themselves in the Land? (i.e. Abraham was apprehensive about himself and his descendants: would they be sufficiently worthy?) His question is therefore to be interpreted as if the verse read ‘let me know how’, i.e. by what merit would he receive the Land, and how would his children merit to retain this gift in later generations: perhaps they will sin and forfeit all.
God answered: ‘By the merit of the sacrifices’ which you are about to offer, and which I will institute as a means of atonement for your children. And because God would forgive Israel on account of their repentance and prayer for which sacrifices are a symbol.
The Talmud (Megillah 31b) on which Rashi’s latter comment is based continues: Abraham then said to Him: Sovereign of the Universe, this is very well for the time when the Temple will be standing, but when there will be no Temple what will befall them? … God replied: I have already established for them the Order of the Sacrifice said during prayers. Whenever they will read the section dealing with sacrifices I will consider it as if they were bringing Me an offering and forgive all their iniquities.
Ramban similarly explains that Abraham’s request is not to be interpreted as asking for a sign as did Hezekiah in II Kings 20:8. Neither did God give him one. Rather, Abraham merely asked that he might know with a true inner knowledge that the gift of the Land would be an enduring one unaffected by his sin or that of his descendants. Additionally, he feared that the Canaanites who were in the Land and had to be driven away before Abraham’s descendants could inhabit it, might repent and thereby deserve to remain in the Land. (See Jeremiah 18:7-8). God therefore assured him that he would inherit the Land despite all possible circumstances.
A covenant is a permanent bond between two parties, symbolizing a friendship so close that they are like a single body and that each is as responsible for the other as for himself.
Symbolic of this they cut an animal in two and pass between the parts, to signify that just as disease or injury afflicting one half of the animal affected the entire animal when it was a single, living organism, and only death separated the two parts – similarly, the two parties entering into the covenant are to be as one body, each ready to risk danger, if necessary, to help the other.
At the same time, each must reveal to the other his innermost thoughts, and not withhold knowledge about evil plots against the other.
Therefore, as soon as God made a covenant with Abraham, He made known to him the evil that was destined to befall his descendants, symbolically showing him the subjugation of Israel to other nations, but simultaneously comforting him with the knowledge that “afterward they shall leave with great wealth” (verse 14)…
Thus, the covenant symbolized that God would be with Israel in distress just as the whole body shares in the pain of one of its limbs. Our Sages say: The Shechinah suffers with the suffering of Israel, as is said in Psalm 91:15, ‘I will be with him in trouble’.
15:9 God commanded him to take the following animals to seal the covenant and to give it the additional status of an irrevocable oath. It was to this that Moses later referred when he said to the Israelites (Deuteronomy 9:5): ‘It is not for your righteousness…that you go to possess their land, but because of the wickedness of these nations Hashem is driving them out before you, and in order to fulfill the oath that Hashem swore to your fathers. (i.e., even if you do not merit possession of the Land, God must fulfill His oath.) (Sforno)
“..three heifers,” – Symbolic of the three sacrifices of bulls which would later be brought on Yom Kippur (Numbers 29:8); the bull which was brought when the whole congregation sinned unintentionally by acting on certain types of erroneous decisions of the Sanhedrin (Leviticus 4:13-21); and the heifer whose neck was to be axed (Deuteronomy 21:4).
“..three goats..” – Symbolic of the goat which was offered within the Temple on Yum Kippur (Leviticus 16:15); the goats brought as additional offerings on Festivals (Numbers 28:15, 22,30); and the goat brought as a sin offering, by an individual (Leviticus 4:28) (Rashi).
“three rams,..” – Symbolic of the guilt offering for definite commission of certain offenses (see Leviticus 5:15; 14:24; 19:21; Numbers 6:12); the guilt offering when there is doubt whether an offense was committed (Leviticus 5:17-19); and the lamb brought as a sin offering, by an individual (Leviticus 4:32) (Rashi).
“..a turtledove and a young dove.” – Radak explains that the Hebrew word for young dove refers to any fledgling bird, just as young eagles are called in Deuteronomy 32:11. The translation defining it here as ‘young dove’ follows the Midrash.
In choosing the animals listed in this verse, God alluded to future sacrifices of cattle and fowl all of which would be solely from these species.
15:10 God was making a covenant with Abraham that He would bequeath the Land to his children as expressly mentioned in verse 18. Therefore, in the plain sense, the cutting of the animals, the passing between the parts, and all that ensued must be interpreted as the ritual of those who enter covenant.
Abraham placed the turtledove and the young dove opposite one another for they were both included in the covenant, but he did not divide them in half, since regarding the fowl that is offered up, the Torah states (Leviticus 1:17); ‘he shall not divide’ Ramban).
The symbolism of the animals chosen is that the nations of the world are compared to ‘bulls’ (see Psalms 22:13, Pharisees), ‘rams’ (Daniel 8:3 Media and Persia), and ‘goats’ (verse 21 = Greece). Israel is compared to young doves (Song of Songs 2:14). To indicate that the nations were destined to decline, Abraham divided the animals, but the birds he did not cut up suggesting thereby that Israel will live forever (Rashi).
Rav Eliezer said: At the Covenant Between the Parts, God showed our father Abraham the Four Kingdoms – Babylon, Persia-Media, Greece and Rome – their dominion, and their downfall.
15:11 There was nothing unusual in birds of pray swooping down on carcasses. That this warranted special mention in the Torah, let the commentators to seek a symbolic interpretation.
The objective of the heathens in time to come would be to attack the spiritual strength of Israel by overturning the divine service. By severing the spiritual link between God and Israel – the offerings and the study of Torah – the people would be spiritually asphyxiated. God’s promise, therefore, was that the ‘birds of prey’ would be driven away without attaining their goal.
15:12 “..a deep sleep..” – It was the deep sleep that accompanies prophetic manifestations. Compare Daniel’s prophetic slumber (Daniel 8:18) “As He was speaking with me, I fell into a deep sleep on my face toward the ground..” This was followed by a dark dread (Daniel 8:17) “and when He approached me I was afraid.” (Radak)
During the previous vision Abraham did not experience all of this, because the previous tidings were good. Now that God came to reveal the darkness and bitterness of the future exiles, He cast the deep sleep, fear, and darkness upon him to symbolize the difficult tribulations that lay ahead. (Rashi; Radak)
According to the Midrash, the fourfold expression, dread, darkness, great, and fell – all of which overtook his soul sequentially – referred to the Four Kingdoms. The dread is Babylon; darkness is Media-Persia; great is Greece; fell is Rome. Thus, Ramban explains, God forewarned Abraham that if Israel sinned, they would be exiled from their land by these four powers. Following this general allusion, He explicitly told him that their possession of the Land would be preceded by the Egyptian exile.
15:13 God, Who has entered into a Covenant with Abraham, withholds nothing from His beloved, and reveals to him the future plight of his descendants.
Abraham is now told that although the land is assured him, actual possession of it will be delayed ‘because the iniquity of the Amorite is not yet full’ (verse 16), and a nation cannot be expelled from its land until it has sinned to the point where God no longer forbears from depriving it of its homeland. During the interim his offspring shall be an alien nation. Not all will suffer servitude, however, for the bondage did not begin during the lives of the righteous; the servitude did not begin until after the death of Jacob’s sons when it was deserved by their sinful children. He revealed all this to Abraham so that the last generation should know that whatever befell them was by the Word of Hashem, and they should attribute it to no other cause, as the prophet declared (Isaiah 48:5): “I have already from the beginning told it to you; announced things to you before they happened” that you might not say ‘My idol has caused them; my carved and molten images commanded them’”. (Sforno)
It was with the birth of Isaac thirty years after this Covenant (Abraham was seventy at the time of the Covenant and one hundred at Isaac’s birth) that the 400 year calculation in this prophecy would begin.
Rashi notes that the verse does not specify Egypt because the exile in Egypt lasted for only 210 out of the 400 years. The 400 year period of exile began with the birth of Isaac, for it was from that time onward that the family of Abraham was treated as aliens, even when they lived in Canaan as Isaac did all his life. Thus the Torah states that soon after Isaac’s birth Abraham lived as a stranger, an alien in the land of the Philistines (21:34); Isaac himself was commanded to live in the land (26:3); Jacob lived in the land of Ham, (Psalms 105:23), while his sons said that they came to Egypt to live temporarily (47:4).
After the exile-alien status, came this more severe phase of the Bondage. It came to pass after the death of Joseph, when the Egyptians set taskmasters over the Jews (see Exodus 1:11). (Malbim)
“..and they will oppress them..” – The oppression began with the birth of Miriam. This is based upon the Midrashic interpretation that Moses’ sister was named Miriam, which literally means bitterness, because at the time of her birth the Egyptians increased the bitterness of the bondage upon the Jews, as it says in Exodus 1:14 “they embittered their lives”. Thus, the harshest part of the 210 years of the Egyptian bondage was the 86 years from the birth of Miriam.
The exile and especially the grinding servitude in Egypt must be seen from the perspective of an iron crucible, as the Torah describes Egypt (Deuteronomy 4:20). A crucible, by melting precious metal, removes the impurities from it. The purpose of exile in God’s plan for Israel is to purify and elevate the nation. The extent of the suffering, however, will be increased if Israel is sinful.
Note: Rashi clarifies the chronology: The period of 400 years extends from Isaac’s birth until the Exodus. This total is arrived at because Isaac was 60 years old when Jacob was born (25:26); Jacob, as he himself stated (Genesis 47:9), was 130 years old when he went down to Egypt, making a total of 190 years. They were actually in Egypt for 210 years, the numeric equivalent of 400 years altogether.
In Exodus 12:40 the length of Israel’s stay in Egypt is given as four hundred and thirty years, while in our verse hour hundred years is foretold. The texts are not contradictory, however. The additional thirty year period refers to the years between the Covenant (when Abraham was 70) and Isaac’s birth when Abraham was 100. This encompasses the period that Abraham, himself, was a stranger.
Abraham’s sojourning was unlike that of his children. Even while wandering, he was always welcomed. Even though he was a stranger, he was held in the highest esteem as (23:6) ‘a prince of God’. Therefore, perhaps, Abraham’s travels are not included in the initial 400 years which began with Isaac, because the nature of Abraham’s travels are different from those of his descendants. They are mentioned as part of the additional thirty years mentioned in Exodus, because they did, in fact, take place, but they are different in kind, rather than degree, from the sort of sojourning inflicted upon Isaac and his descendants.
15:14 ‘..the nation which they serve..’ – Hirsch’s interpretation: The nation that I have appointed for a fiery furnace, a melting pot for your descendants, is told here that when it’s mission is accomplished, it will suffer the fate it will have richly earned.
Egypt as God’s Agent
This verse evokes certain profound philosophical questions which touch on the very foundations of man’s Free-Will and God’s Foreknowledge; reward and punishment. If God decreed that Abraham’s descendants should be strangers in a land not their own, where they would be subjected to servitude and affliction, then why should the Egyptians be punished for having been the agents in the carrying out God’s Providential Will?
Rambam answers that God was not addressing the Egyptians when He uttered this decree, nor did He decree that any one person in particular should enslave the Jews. God was merely instructing Abraham as to the course of future history. Just as no one similarly has the right to be wicked because the Almighty has informed Moses that there will be wicked men among Israel, so, too, with the Egyptians: every Egyptian who oppressed and ill-treated the Israelites could have refrained from doing so had he not wished to hurt them. Since he did perpetrate these acts, however, he is subject to punishment. Even had no Pharaoh arisen, Israel was destined to servitude, as God specifically foretold. But good is brought through the worthy, while evil is brought through the guilty. Pharaoh was chosen for this mission because he was wicked, and therefore he deserved punishment. (Semachos 8)
Ramban explains that the Egyptians were punished not for executing God’s decrees but for their overzealousness in carrying it out: It was not included in His decree that they should throw Jewish children into the Nile, for this was not ‘affliction’ – it was murder. The same applies to the general severity and vigor which they displayed toward the Israelites.
This is also the case with Nebuchadnezzar, who, though the prophets unanimously called
upon him and his people to destroy Jerusalem (see Jeremiah 25:9; 32:28-29), and though the Chaldeans were aware that this was the command of God, nevertheless they were all punished because Nebuchadnezzar had his own personal glory in mind (see Isaiah 14:13-14; and 47:8), and because he added to the decree and overzealously perpetrated evil against Israel (see Isaiah 47:6).
“they shall leave with great possessions…” – Their wealth could not possibly be considered payment for the years of bitter enslavement and countless deaths, pain, and suffering inflicted upon the Israelites by the Egyptians. Rather, what Abraham is being assured here is that when the time of redemption arrives, the awful past will not be recognizable in his descendants. They will leave Egypt not as pitiful slaves escaping from their master but as a content nation which has gathered wealth and possessions.
15:15 “..you shall be buried in a good old age.” – A Scriptural idiom meaning: spared from all suffering. By this promise, God announced to him that Ishmael would repent in Abraham’s lifetime, and that his grandchild Esau would not go on the wicked path in his lifetime. To prevent Abraham from witnessing Esau’s evil conduct, however, Abraham died five years earlier than he normally would have, because on the very day Abraham died Esau rebelled, Had Abraham lived, he would have witnessed it.
This is based on the Midrash which notes that Abraham was destined to live 180 years like his son Isaac, but that God withheld five years of Abraham’s life in anticipation of Esau’s sins, as God said, I promised Abraham, you shall be buried in a good old age. Is it a good old age when he sees his grandson commit adultery and murder? It is better to have him die in peace!
15:16 HaChaim writes that there are two distinct terms given in this verse – one for the end of the exile and another for the entry into the Land. The exile would last no longer than 400 years. The time of entry into the Land however, would be more flexible – the fourth generation – and it would be sooner or later within the lifetime of that generation, depending on the degree of its righteousness. The ‘four generations’ begin from the time the Egyptian servitude was imposed which was after the death of Jacob’s twelve sons. Thus, the four are Perez, Chezron, Caleb, and Caleb’s children. (Although Caleb entered the Land, he is not counted because the rest of his generation died in the wilderness.) The verse continues that the sins of the Amorites are also a determining factor. Had Israel been perfect in its righteousness, then the Amorites would have had to make way for them. However, since Israel sinned and could not be considered perfect, a different measuring rod was required. Israel was better than the Amorites, but not perfect. Therefore, the entry into the Land was delayed until the Amorite’s allotted measure of sin was reached.
The Amorite represents all the Canaanite nations. It is singled out because it was the most powerful of them all, being described as ‘tall as cedars’ (Amos 2:9).
This is the crux of the entire prophecy: The Promised Land will not be given now, but to the fourth generation because only by then will the iniquity of the Amorites have reached sufficient dimension to warrant their expulsion from the Land. Another reason why God specified the Amorites is because Abraham then dwelled in the territory of Mamre, and Amorite. (Hoffmann)
The Ratification of the Covenant
15:17 “..and it was very dark.” – The Word signifies ‘thick darkness’. It is found nowhere else in Scriptures except for three times in Ezekiel (12:6, 7, 12). The darkness was so all-enveloping that even the light of the stars was not visible. (Ibn Ezra)
“..smoky furnace and a torch of fire..” – a vision symbolic of the Divine Presence and all of this occurred during Abraham’s prophetic slumber. He envisioned these things. The smoke (which rose up into the thick darkness (Radak) was the ‘Cloud and thick darkness’ which appeared at the revelation of the Torah; and the torch in its midst was ‘the fire’ which appeared at Sinai (see Exodus 19:18; Deuteronomy 5:4).
“which passed between these pieces.” – In fulfillment of the Covenant. As pointed out, Abraham did not pass through because he undertook no obligation under the terms of this Covenant. It was God Who was obligated under this Covenant regarding the gift of the Land, and as such, He caused His Presence, symbolized by the fire, to pass through and conclude the Covenant.
This verse uses the word ‘pieces’ instead of the word ‘carcasses’ as in verse 11. The use of the more respectful word in our verse is in reference to the Shechinah, which passed between the pieces. (Ralbag)
15:18-21 The everlasting Covenant between God and Abraham was ratified by the events that occurred on that day: the visions, the division of the animals, the passing through of the Divine Presence and His Promise.
Ramban comments that the promise of the Land was given to Abraham several times, each of them necessary. When he originally entered the country, God told him (12:7): ‘To your seed, I will give this Land’, a pledge which only included the territory which he had traveled until then. When his merits increased, God bestowed the additional promise (13:14-15): ‘Lift up your eyes…All the land which you see, to you will I give it and your seed forever.’ This promise was more comprehensive and also added ‘and to your seed forever’, and that his seed would increase ‘as the dust of the earth.’ In this chapter, God defines the boundaries of the Land, mentioning the ten nations which presently occupied the Land and would be displaced (verses 19-21) and further made an irrevocable covenant with him that could not be revoked through sin. When He repeated the promise on the occasion of Abraham’s circumcision for the final time, He added the words (17:8) “for a possession forever’, which meant that even if they were to be exiled, they would return and inherit it.
Rashi notes that although ten nations are mentioned here, God gave Israel the territory only of seven (Deuteronomy 7:1). The other three: Edom, Moab, and Ammon (identified respectively with the Kenites, Kenizzites, and Kadmonites in this verse), will become Israel’s possession only in the future (see Isaiah 11:14).
The Midrash sums up with a note on the association of this verse with the next (16:1), which might also explain why the above verses of the Covenant Between the Parts, were placed here even though, according to the Sages, they are not in correct chronological sequence: The Holy One, Blessed by He, originally contemplated giving Israel possession of ten peoples, but He gave them only seven… Edom, Moab, and Ammon being the three nations that were not given them in this world… But in the days of the Messiah they shall once again belong to Israel (i.e., they had already belonged to Israel in accord with God’s promise) in fulfillment of God’s promise. Now, He has given them all but seven…