13 Be sure you circumcise those born in your household and those purchased with your silver. Your flesh will embody my covenant as an enduring covenant.
14 Any uncircumcised male whose flesh of his foreskin remains uncircumcised will be cut off from his people. He has broken my covenant."
15 God said to Abraham, "As for your wife Sarai, you will no longer call her Sarai. Her name will now be Sarah.
16 I will bless her and even give you a son from her. I will bless her so that she will become nations, and kings of peoples will come from her."
17 Abraham fell on his face and laughed. He said to himself, Can a 100-year-old man become a father, or Sarah, a 90-year-old woman, have a child?
18 To God Abraham said, "If only you would accept Ishmael!"
19 But God said, "No, your wife Sarah will give birth to a son for you, and you will name him Isaac. I will set up my covenant with him and with his descendants after him as an enduring covenant.