In that day Jehovah made a covenant with Abram, saying, Unto thy seed have I given this land, from the river of Egypt unto the great river, the river Euphrates: the Kenite, and the Kenizzite, and the Kadmonite, and the Hittite, and the Perizzite, and the Rephaim, and the Amorite, and the Canaanite, and the Girgashite, and the Jebusite.Genesis 15:18-21 ASV
This must be understood in the sense that God ratified and confirmed with this ancient type of oath the covenant already existing, and which was recounted in Genesis 12:1f.
This great compound of seven elements is referred to above in the passage from Hebrews as “the promise,” that is the great, universal and perpetual promise.
For when God made promise to Abraham, since he could swear by none greater, he sware by himself, saying, Surely blessing I will bless thee, and multiplying I will multiply thee. And thus, having patiently endured, he obtained the promise.Hebrews 6:13-15 ASV
The reference to Abraham in Hebrews 6, is for the purpose of holding him up as an example.
He was the most illustrious of the patriarchs and prophets, of whom the author had already said that his readers should imitate them.
There seems also to be a special reason for singling out Abraham at this point, due to his importance in what happened with Melchizedek, and which events the author will more fully develop a little later in the epistle.
The patience of Abraham was indeed exemplary for several reasons.
The promise, it will be remembered (Genesis 12:1ff), envisioned a great posterity for Abraham; but many years passed during which he had no son. Passing over the incident involving Hagar, Abraham waited patiently for that which, according to all human reckoning, was impossible.
Then at last, when Isaac was born, and the patriarch’s hopes and affections were centered in him, his patience was further tested by the astounding command of God that Isaac should be offered as a sacrifice.
The nearly superhuman response of Abraham to that commandment of God became the occasion for God’s confirming the promise with an oath.
The statement here that Abraham “obtained” the promise has reference to his receiving in full faith the prospect of its ultimate fulfillment when Isaac was restored to him, which was like receiving him back from the dead (Hebrews 11:19).
There was a sense in which Abraham did not truly receive the promise (Hebrews 11:39), that is, “all” of the promise; nor will he do so until all the faithful of all times receive it all together in the eternal home of the soul.
This is also referenced in Galatians 3:29, with regard to Abraham’s seed.
And if ye are Christ’s, then are ye Abraham’s seed, heirs according to promise.Galatians 3:29 ASV
This is not merely a continuation of the argument Paul has been making, but it is continued into Galatians 4.
This enabled the Gentiles to be accounted the true seed of Abraham, bypassing the Law of Moses altogether, thus inheriting through the promise to Abraham (Genesis 12:3; 18:18; 22:18).
Those who believe in Christ and are baptized in him are to be understood as here being affirmed to be “Abraham’s seed,” because, being clothed with Christ, they share his position.
“Heirs …” They are heirs, not of Abraham, but of God; for the idea connects to that of the sonship to God (Galatians 3:26), of believers in Christ.
The Seven-fold Promise
The elements of it are:
I will make of thee a great nation.
And I will bless thee.
And I will make thy name great.
And be thou a blessing;
And I will bless them that bless thee.
And I will curse him that curseth thee,
And in thee shall all the families of the earth be blessed. (Genesis 12:2,3).
He also elaborated significant details not previously given:
Abram himself would not inherit the land at all, but it would be possessed by his posterity.
Even his seed would not possess the land until centuries should pass and the iniquity of the Amorite should have run its course and reached a fullness requiring their dispossession.
In the 400 years preceding the ultimate possession of the land by Israel, the people would undergo slavery and affliction.
The nation that would thus subject them would be severely judged.
The Jews would finally leave the land of their oppression with great wealth.
The actual boundaries of Israel’s ultimate domain were given. Such a great wealth of additional information more than justified the statement that,
“In that day God made a covenant, etc. …” “From the river of Egypt … the river Euphrates …” This would seem to say, “From the Nile,” since that great river could also be called “the river of Egypt,”
This is probably the Wady of Arish on the border of Egypt.
This was precisely fulfilled in the days of the Solomonic Empire which embraced all of the territory included here.