Genesis 17:15

He who is eight days old shall be circumcised among you, every male throughout your generations, he who is born in the house, or bought with money from any foreigner who is not of your offspring.

He who is born in your house, and he who is bought with your money, must be circumcised. My covenant shall be in your flesh for an everlasting covenant.

The uncircumcised male who is not circumcised in the flesh of his foreskin, that soul shall be cut off from his people. He has broken my covenant.”

I will bless her, and moreover I will give you a son by her. Yes, I will bless her, and she will be a mother of nations. Kings of peoples will come from her.”

Then Abraham fell on his face, and laughed, and said in his heart, “Will a child be born to him who is one hundred years old? Will Sarah, who is ninety years old, give birth?”

Abraham said to God, “Oh that Ishmael might live before you!”