Jeremiah 34:14-15

14‘Every seventh year each of you must free any fellow Hebrews who have sold themselves to you. After they have served you six years, you must let them go free.’ Your ancestors, however, did not listen to me or pay attention to me. 15Recently you repented and did what is right in my sight: Each of you proclaimed freedom to your own people. You even made a covenant before me in the house that bears my Name.