Genesis 17:15-27

God said to Abraham, “I will change the name of Sarai, your wife, to Sarah. I will bless her and give her a son, and you will be the father. She will be the mother of many nations. Kings of nations will come from her.” Abraham bowed facedown on the ground and laughed. He said to himself, “Can a man have a child when he is a hundred years old? Can Sarah give birth to a child when she is ninety?” Then Abraham said to God, “Please let Ishmael be the son you promised.” God said, “No, Sarah your wife will have a son, and you will name him Isaac. I will make my agreement with him to be an agreement that continues forever with all his descendants. “As for Ishmael, I have heard you. I will bless him and give him many descendants. And I will cause their numbers to grow greatly. He will be the father of twelve great leaders, and I will make him into a great nation. But I will make my agreement with Isaac, the son whom Sarah will have at this same time next year.” After God finished talking with Abraham, God rose and left him. Then Abraham gathered Ishmael, all the males born in his camp, and the slaves he had bought. So that day Abraham circumcised every man and boy in his camp as God had told him to do. Abraham was ninety-nine years old when he was circumcised. And Ishmael, his son, was thirteen years old when he was circumcised. Abraham and his son were circumcised on the same day. Also on that day all the men in Abraham’s camp were circumcised, including all those born in his camp and all the slaves he had bought from other nations.