Genesis 17:21

For Sarah conceived, and bare Abraham a son in his old age, at the set time of which God had spoken to him. And Abraham called the name of his son that was born unto him, whom Sarah bare to him, Isaac.

And the Lord appeared unto him, and said, Go not down into Egypt; dwell in the land which I shall tell thee of: Sojourn in this land, and I will be with thee, and will bless thee; for unto thee, and unto thy seed, I will give all these countries, and I will perform the oath which I sware unto Abraham thy father; And I will make thy seed to multiply as the stars of heaven, and will give unto thy seed all these countries; and in thy seed shall all the nations of the earth be blessed; Because that Abraham obeyed my voice, and kept my charge, my commandments, my statutes, and my laws.

And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.

And he said, I will certainly return unto thee according to the time of life; and, lo, Sarah thy wife shall have a son. And Sarah heard it in the tent door, which was behind him.

Whose are the fathers, and of whom as concerning the flesh Christ came, who is over all, God blessed for ever. Amen. Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:

And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.

And God heard their groaning, and God remembered his covenant with Abraham, with Isaac, and with Jacob.

Moreover he said, I am the God of thy father, the God of Abraham, the God of Isaac, and the God of Jacob. And Moses hid his face; for he was afraid to look upon God.

Wherefore she said unto Abraham, Cast out this bondwoman and her son: for the son of this bondwoman shall not be heir with my son, even with Isaac. And the thing was very grievous in Abraham’s sight because of his son. And God said unto Abraham, Let it not be grievous in thy sight because of the lad, and because of thy bondwoman; in all that Sarah hath said unto thee, hearken unto her voice; for in Isaac shall thy seed be called.

And Israel took his journey with all that he had, and came to Beer–sheba, and offered sacrifices unto the God of his father Isaac.

By faith he sojourned in the land of promise, as in a strange country, dwelling in tabernacles with Isaac and Jacob, the heirs with him of the same promise:

O that thou wouldest hide me in the grave, that thou wouldest keep me secret, until thy wrath be past, that thou wouldest appoint me a set time, and remember me!

As he spake to our fathers, to Abraham, and to his seed for ever.

To perform the mercy promised to our fathers, and to remember his holy covenant;

For this is the word of promise, At this time will I come, and Sara shall have a son.

And he blessed Joseph, and said, God, before whom my fathers Abraham and Isaac did walk, the God which fed me all my life long unto this day,