Deuteronomy 15:12
And if your brother, a Hebrew man, or a Hebrew woman, be sold unto you, and serve you six years; then in the seventh year you shall let him go free from you.
Jeremiah 34:14
At the end of seven years let you go every man his brother, a Hebrew, who has been sold unto you; and when he has served you six years, you shall let him go free from you: but your fathers hearkened not unto me, neither inclined their ear.
Leviticus 25:39-41
And if your brother that dwells by you becomes poor, and is sold unto you; you shall not compel him to serve as a slave:
Exodus 21:2-6
If you buy a Hebrew servant, six years he shall serve: and in the seventh he shall go out free for nothing.
Deuteronomy 15:1
At the end of every seven years you shall make a release.
John 8:35-36
And the servant abides not in the house forever: but the Son abides ever.