Genesis 17:21

21 But my covenant I will establish with Isaac, whom Sarah shall bear to you at this season next year."

Genesis 17:21 Meaning and Commentary

Genesis 17:21

But my covenant will one establish with Isaac
The covenant of circumcision; for though Ishmael was circumcised, and his posterity practised that rite, yet it was not enjoined them of God; nor was it to them, or served the same purpose as to the Israelites; and particularly the promise of the land of Canaan, made in that covenant, belonged only to the posterity of Isaac, and to those only in the line of Jacob, and especially that of the Messiah springing from him, which circumcision had a respect unto:

whom Sarah shall bear unto thee, at this set time, in the next year:
that is, at the end of nine months, which is the set time a woman goes with child.

Genesis 17:21 In-Context

19 God said, "No, but your wife Sarah shall bear you a son, and you shall name him Isaac. I will establish my covenant with him as an everlasting covenant for his offspring after him.
20 As for Ishmael, I have heard you; I will bless him and make him fruitful and exceedingly numerous; he shall be the father of twelve princes, and I will make him a great nation.
21 But my covenant I will establish with Isaac, whom Sarah shall bear to you at this season next year."
22 And when he had finished talking with him, God went up from Abraham.
23 Then Abraham took his son Ishmael and all the slaves born in his house or bought with his money, every male among the men of Abraham's house, and he circumcised the flesh of their foreskins that very day, as God had said to him.