Genesis 17:19

17:19 God said, “No, Sarah your wife is going to bear you a son, and you will name him Isaac. I will confirm my covenant with him as a perpetual covenant for his descendants after him.

Genesis 17:21

17:21 But I will establish my covenant with Isaac, whom Sarah will bear to you at this set time next year.”

Genesis 18:10

18:10 One of them said, “I will surely return to you when the season comes round again, and your wife Sarah will have a son!” (Now Sarah was listening at the entrance to the tent, not far behind him.

Genesis 18:14

18:14 Is anything impossible for the Lord? I will return to you when the season comes round again and Sarah will have a son.”

Romans 9:9

9:9 For this is what the promise declared: “About a year from now I will return and Sarah will have a son.”