Genesis 17:19-27

God said, “Listen to me. I promise that you and Sarah will have a son, and you will call him Isaac. I will confirm my everlasting covenant of love with him and his seed. And regarding Ishmael, I have heard your cry and I will indeed bless him. I will cause him to have many, many descendants. He will father twelve rulers, and I will make him into a great nation. But my everlasting covenant relationship is with Isaac, who will be born to you and Sarah about this time next year.” When he had finished speaking with Abraham, God ascended up to heaven. So without delay Abraham obeyed God and took his son Ishmael and every male in his household (whether born in his house or foreign-born servants) and circumcised them that very same day. Abraham was already ninety-nine years old when he was circumcised, and his son Ishmael was thirteen. They were both circumcised on the same day, along with all the men of his household (whether born in his house or foreign-born servants).