Genesis 17:23-27

On that very day Abraham took his son, Ishmael, and every male in his household, including those born there and those he had bought. Then he circumcised them, cutting off their foreskins, just as God had told him. Abraham was ninety-nine years old when he was circumcised, and Ishmael, his son, was thirteen. Both Abraham and his son, Ishmael, were circumcised on that same day, along with all the other men and boys of the household, whether they were born there or bought as servants. All were circumcised with him.