This is another excerpt from the book I am trying to write.
The Abrahamic covenant is pivotal to the history biblical which unfolds thereafter, and Genesis 15 is perhaps the key passage to understand with respect to it. The initiative is God’s, and it is here that God binds Himself by oath to perform the details of the promises He makes to Abraham. It will be useful to reproduce the first part of the chapter.
After these things the word of the LORD came to Abram in a vision, saying, “Do not be afraid, Abram. I am your shield, your exceedingly great reward. 2 But Abram said, “Lord GOD, what will You give me, seeing I go childless, and the heir of my house is Eliezer of Damascus?” 3 Then Abram said, “Look, You have given me no offspring; indeed one born in my house is my heir!” 4 And behold, the word of the LORD came to him, saying, “This one shall not be your heir, but one who will come from your own body shall be your heir.” 5 Then He brought him outside and said, “Look now toward heaven, and count the stars if you are able to number them.” And He said to him, “So shall your descendants be.” 6 And he believed in the LORD, and He accounted it to him for righteousness. 7 Then He said to him, “I am the LORD, who brought you out of Ur of the Chaldeans, to give you this land to inherit it.” – Genesis 15:1-7
Sometime after the blessing from the priest of God Yahweh Himself appears to Abram and reiterates His word of promise. The interchange is instructive. Abram’s immediate response to the vision of God is to ask about a child (cf. 11:30). If the land was going to go to his descendants (zera – “seed”) as God had said (13:15-16), then something needed to happen about Sarai’s condition. As every Bible reader knows, God was to do something about that – eventually! But Abram has been brooding on the promise. And he and his wife would certainly have been sensitive on the matter in any case. He is quite forward with God. There is an air of desperation and even irony in his words; “what will you give me, seeing I go childless…You have given me no seed.”
Little did he know that many more years were to pass by until God finally came through. At a time when all hope seemed lost, God showed He was as good as His word. This ought to remind the reader that God will perform exactly what He has said He will do in regard to Abraham’s descendants (national Israel in the context – 15:13) although it appears to many that their time is passed.
The Lord’s reply reassures Abram that his original expectation based on God’s promise (12:2a), was accurate. “This one shall not be your heir, but one who will come from your own body shall be your heir.” (15:4). And yet, every reader of the Bible knows that his trial of waiting for a son was far from over. But Abram did believe what God said to him, not only about an heir, but also about his descendants. Faith in God’s promise is faith in His character, and God’s character can only be trusted if His words can be trusted. Abram’s faith in the promise glorified God and God’s response was to justify Abram as righteous before Him.
The context is very clear that the content of the declaration by God concerning the stars of the heaven and the sand on the seashore evoked trust in Abram and that God reckoned that trust as righteousness to Abram’s account. Abram was not presented with a message about a crucified and risen Messiah. He wouldn’t have known what crucifixion was in any case. When the Apostle uses Genesis 15:6 in his argument for justification he repeats the content of the message while observing the response of God to Abram’s faith (Rom. 4:3-5; Gal. 3:6-7). The onus for Paul is on the faith in God, not on what Abram believed.
Upon the heels of this faith/righteousness transaction the very next thing that comes up is the gift of the land (15:7). For the writer of Genesis, as in the Old Testament generally, the seed and the land belong together. They ought not to be separated in our theology. It is to the subject of the land that the chapter now turns.
8 And he said, “Lord GOD, how shall I know that I will inherit it?” 9 So He said to him, “Bring Me a three-year-old heifer, a three-year-old female goat, a three-year-old ram, a turtledove, and a young pigeon.” 10 Then he brought all these to Him and cut them in two, down the middle, and placed each piece opposite the other; but he did not cut the birds in two. 11 And when the vultures came down on the carcasses, Abram drove them away. 12 Now when the sun was going down, a deep sleep fell upon Abram; and behold, horror and great darkness fell upon him. 13 Then He said to Abram: “Know certainly that your descendants will be strangers in a land that is not theirs, and will serve them, and they will afflict them four hundred years. 14 “And also the nation whom they serve I will judge; afterward they shall come out with great possessions. 15 “Now as for you, you shall go to your fathers in peace; you shall be buried at a good old age. 16 “But in the fourth generation they shall return here, for the iniquity of the Amorites is not yet complete.” 17 And it came to pass, when the sun went down and it was dark, that behold, there appeared a smoking oven and a burning torch that passed between those pieces. 18 On the same day the LORD made a covenant with Abram, saying: “To your descendants I have given this land, from the river of Egypt to the great river, the River Euphrates– 19 “the Kenites, the Kenezzites, the Kadmonites, 20 “the Hittites, the Perizzites, the Rephaim, 21 “the Amorites, the Canaanites, the Girgashites, and the Jebusites.” – Genesis 15:8-21
Abram wants to know how he will inherit the land which God has brought him to. A fair question seeing as he didn’t own any of it (cf. Acts 7:5). These verses are critical to understand for anyone concerned with the covenants of the Bible. This is true because of several factors. First, the passage explicitly deals with the land. The land is, as we have seen, central to the Abraham story. This means that a theology which ignores the land will never be in a position to interpret the Abrahamic covenant correctly, because here it is absolutely central to God’s covenant-making act. Second, the verses include a self-malediction oath taken by God Himself. Experts go back and forth on whether such oaths were the convention in Old Testament times. As far as Scripture goes, the only other instance of such an oath is found in Jeremiah 34, where King Zedekiah and his nobles are said to have taken such a measure and to have gone back on it. Thirdly, God reveals to Abram that he in fact will not himself live to inherit the land, but that he will die after living well into old age. In the fourth place, the covenant expressly joins Abram’s descendants together with the land that Abram has been brought into, but only after they have been absent from it for four hundred years. This introduces a fifth factor; that unlike the Noahic covenant before it this covenant includes within it a distinct prediction about Israel. Then also, the geographical limits of the land are given so that there can be no question about what Abram’s descendents will eventually inherit. Finally, since Abram is put into a deep sleep while the Lord takes the oath this is clearly an unconditional covenant, as all but a few dyed-in-the-wool supercessionists acknowledge.
The animals which Abram divides (vv. 9-10), are clean animals designated by God. Although some have seen portents of Israel’s future in the driving away of the birds, it seems rather commonsensical to us that Abram would have had enough about him to protect the sacred scene until Yahweh came. In the same vein the “fourth generation” of verse 16 is probably meant to convey nothing more than that simple fact. But the prediction does underscore the literal meaning of the whole revelation.
 So John H. Sailhamer, who writes, “The two central narratives that feature Abraham’s covenant with God are Genesis 15 and Genesis 1. Both chapters represent major compositional staging points in the overall literary and theological strategy of the Pentateuch. However, Genesis 15 surpasses all other chapters in the Pentateuch in presenting the nature and purpose of the Abrahamic covenant and blessing.” – The Meaning of the Pentateuch, 436-437.
 I will return to this theme. Suffice it for now that the message of the Gospel includes the content which now must be believed for righteousness to be reckoned to us by God. See, e.g., Charles C. Ryrie, Dispensationalism, 115-117
 See, e.g., W. J. Dumbrell, Covenant and Creation, 47-49; D. J. McCarthy, Treaty and Covenant, 91.
 “God initiated it with Abraham unilaterally, Abraham’s only responsibility being to accept it; and its promises likewise were guaranteed of fulfillment no matter how faithful Abraham might be to its terms.” – Eugene H. Merrill, Everlasting Dominion, 326