Jeremiah 34:10-11

And all the officials and all the people obeyed who had entered into the covenant that each man should set free his male servant and each man his female servant, so that no one should keep them any longer in bondage; they obeyed, and set them free. But afterward they turned around and took back the male servants and the female servants whom they had set free, and brought them into subjection for male servants and for female servants.