Adam Clarke on Genesis 17:13

He that is born in thy house - The son of a servant; he that is bought with thy money - a slave on his coming into the family. According to the Jewish writers the father was to circumcise his son; and the master, the servant born in his house, or the slave bought with money. If the father or master neglected to do this, then the magistrates were obliged to see it performed; if the neglect of this ordinance was unknown to the magistrates, then the person himself, when he came of age, was obliged to do it.