Jeremiah 34:9-14

9Everyone was supposed to free his Hebrew slaves, both male and female. No one was supposed to keep another Jew as a slave.

10All the officials and all the people agreed and promised to free their male and female slaves and not to keep them as slaves anymore. So they set them free.

11But afterwards, they changed their minds and took back the men and women they had freed and made them their slaves again.

12The Lord spoke his word to Jeremiah. He said,

13“This is what the Lord God of Israel says: I put a condition on the promise  I made to your ancestors when I brought them from Egypt, where they were slaves. I said,

14‘Every seven years each of you must free any Hebrews who sold themselves to you. When they have served you for six years, you must set them free.’ But your ancestors refused to obey me or listen to me.