Genesis 17:13-17

A slave who is born in your house or who is bought with your money shall certainly be circumcised; so My covenant shall be in your flesh as an everlasting covenant.

But as for an uncircumcised male, one who is not circumcised in the flesh of his foreskin, that person shall be cut off from his people; he has broken My covenant.”

Then God said to Abraham, “As for your wife Sarai, you shall not call her by the name Sarai, but Sarah shall be her name.

I will bless her, and indeed I will give you a son by her. Then I will bless her, and she shall 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 a man a hundred years old? And will Sarah, who is ninety years old, give birth to a child?”