Berĕshith (Genesis) 17:12-13

“And a son of eight days is circumcised by you, every male child in your generations, he who is born in your house or bought with silver from any foreigner who is not of your seed. “He who is born in your house, and he who is bought with your silver, has to be circumcised. So shall My covenant be in your flesh, for an everlasting covenant.