Deuteronomy 15:16

“If you buy a Hebrew slave, he shall serve for six years; but on the seventh he shall go out as a free man without payment.

“But if the slave plainly says, ‘I love my master, my wife, and my children; I will not go out as a free man,’

‘If a brother of yours becomes so poor with regard to you that he sells himself to you, you shall not subject him to a slave’s service.

“You shall not oppress a hired person who is afflicted and needy, whether he is one of your brothers or one of your sojourners who is in your land within your gates.