Jeremiah 34:13-16

13"Thus says the Lord, the God of Israel: I myself made a covenant with your fathers when I brought them out of the land of Egypt, out of the house of slavery, saying,

14'At the end of seven years each of you must set free the fellow Hebrew who has been sold to you and has served you six years; you must set him free from your service.' But your fathers did not listen to me or incline their ears to me.

15You recently repented and did what was right in my eyes by proclaiming liberty, each to his neighbor, and you made a covenant before me in the house that is called by my name,

16but then you turned around and profaned my name when each of you took back his male and female slaves, whom you had set free according to their desire, and you brought them into subjection to be your slaves.