10. This is My covenant, which you shall observe between Me and between you and between your seed after you, that every male among you be circumcised. 11. And you shall circumcise the flesh of your foreskin, and it shall be as the sign of a covenant between Me and between you. 12. And at the age of eight days, every male shall be circumcised to you throughout your generations, one that is born in the house, or one that is purchased with money, from any foreigner, who is not of your seed. 13. Those born in the house and those purchased for money shall be circumcised, and My covenant shall be in your flesh as an everlasting covenant.
Lech-Lecha, G-d commands Abraham to circumcise himself, his son Isaac, and all his man servants.