Genesis 17:23-27 - Abraham's Household Circumcised
23 And Abraham took Ishmael his son, and all the servants born in his house, and all that was bought with money; as many as were men children among the men of Abraham's house, and circumcised the foreskin of their flesh, even the selfsame day, as God had said unto him. 24 Abraham was ninety years old and nine when he cut off the foreskin of his flesh. 25 And Ishmael his son was thirteen years old, when the foreskin of his flesh was circumcised. 26 The selfsame day was Abraham circumcised and Ishmael his son. 27 And all the men in his house, whether they were born in his house or bought with money, though they were strangers, were circumcised with him.