God made special promises to Abraham and Abraham's descendants.
When GOD called Abraham to leave his homeland to go to Canaan, GOD made Abraham special promises—promises that also applied to Abraham's descendants.
At first, the promises were broad and general.
1 Now the Lord said to Abram, “Get out of your country, from your kindred and from your father's house, to a land I will show you. 2 I will make you a great nation; I will bless you and make your name great; and you shall be a blessing. 3 I will bless those who bless you, and curse those who curse you; and in you all the tribes of the earth shall be blessed.”
(Genesis 12:1-3 OSB)
Abraham believed GOD, so he obeyed and went.
Once Abraham entered the land of Canaan, GOD spoke to him again, saying:
7 Then the Lord appeared to Abram and said, “To your seed I will give this land.”
(Genesis 12:7 OSB)
Later, GOD elaborated on the land promise:
14 Then God said to Abram, after Lot separated from him, “Lift your eyes now and look from the place where you are—northward, southward, eastward, and westward; 15 for all the land you see I give to you and your seed forever. 16 And I will make your seed as the dust of the earth; that if a man could number the dust of the earth, then your seed also could be numbered. 17 Arise, walk in the land through its length and its breadth, for I will give it to you.”
(Genesis 13:14-17 OSB)
Again, GOD spoke to Abraham and was yet more specific and detailed regarding these promises:
1 When Abram was ninety-nine years old, the Lord appeared to Abram and said to him, “I am your God; be pleasing before Me and blameless. 2 I will establish My covenant between Me and you, and will multiply you exceedingly.” 3 Then Abram fell on his face, and God talked with him, saying, 4 “As for Me, behold, My covenant is with you, and you shall be a father of many nations. 5 No longer shall your name be called Abram, but your name shall be Abraham; for I have made you a father of many nations. 6 I will make you exceedingly fruitful; and I will make nations of you, and kings shall come from you. 7 I will establish My covenant between Me and you and your seed after you in their generations, for an everlasting covenant, to be your God and the God of your seed after you. 8 Also I will give you and your seed after you the land you are occupying as a sojourner, all the land of Canaan, as an everlasting possession; and I will be their God.”
9 Then God said to Abraham, “As for you, you shall keep My covenant, you and your seed after you throughout their generations. 10 This is the covenant you shall keep, between Me and you and your seed after you throughout their generations: Every male child among you shall be circumcised; 11 and you shall be circumcised in the flesh of your foreskin. It shall be a sign of the covenant between Me and you. 12 A child of eight days old shall be circumcised by you—every male child throughout your genealogy, he who is born in your house or bought with money from any foreigner not of your seed. 13 He who is born in your house, and he who is bought with your money must be circumcised; and My covenant shall be in your flesh for an everlasting covenant. 14 And the uncircumcised male child, who is not circumcised in the flesh of his foreskin on the eighth day, that soul shall be cut off from his people; for he has broken My covenant.”
(Genesis 17:1-14 OSB)
Yet once more, GOD promised Abraham, saying:
15 Then the Angel of the Lord called to Abraham a second time out of heaven, 16 and said, “By Myself I have sworn, says the Lord, because you did this thing, and for My sake did not spare your beloved son, 17 I will certainly bless you, and assuredly multiply your seed as the stars of heaven and as the sand on the seashore; and your seed shall inherit the cities of their enemies. 18 In your seed all the nations of the earth shall be blessed, because you obeyed My voice.”
(Genesis 22:15-18 OSB)
We have previously established that Abraham's seed referred not to his physical children, but to those who have the faith of Abraham and walk in his example.