Deuteronomy 15:12
If you buy Israelites (your own brothers) as slaves, you must set them free after six years.
Jeremiah 34:14
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.
Leviticus 25:39-41
If an Israelite becomes poor and sells himself to you, do not work him like a slave.
Exodus 21:2-6
When you buy a Hebrew slave he will be your slave for six years. In the seventh year he may leave as a free man without paying for his freedom.
Deuteronomy 15:1
Release all debts at the end of every seven years.
John 8:35-36
The slave does not abide in the house forever. The son abides forever.