Genesis 17:12-13

17:12 Throughout your generations every male among you who is eight days old must be circumcised, whether born in your house or bought with money from any foreigner who is not one of your descendants. 17:13 They must indeed be circumcised, whether born in your house or bought with money. The sign of my covenant will be visible in your flesh as a permanent reminder.

Genesis 17:23

17:23 Abraham took his son Ishmael and every male in his household (whether born in his house or bought with money) and circumcised them on that very same day, just as God had told him to do.