Jeremiah 34:15-16

Then you recently turned and did what was right in My sight—every man proclaiming liberty to his neighbor; and you made a covenant before Me in the house which is called by My name. Then you turned around and profaned My name, and every one of you brought back his male and female slaves, whom you had set at liberty, at their pleasure, and brought them back into subjection, to be your male and female slaves.’