Deuteronomy 15:12
And if thy brother, a Hebrew man, or a Hebrew woman, is sold unto thee and serves thee six years, then in the seventh year thou shalt send him forth from thee free.
Jeremiah 34:14
At the end of seven years each one shall let his Hebrew brother go, who has been sold unto thee; therefore he shall serve thee six years, and thou shalt send him forth free from thee: but your fathers did not hearken unto me, nor incline their ear.
Leviticus 25:39-41
And when thy brother becomes poor, being with thee, and if he should sell himself unto thee, thou shalt not compel him to serve as a slave.
Exodus 21:2-6
If thou should buy a Hebrew slave, he shall serve six years; and in the seventh he shall go out free for nothing.
Deuteronomy 15:1
At the end of every seven years thou shalt make a release.
John 8:35-36
And the slave does not abide in the house for ever, but the Son abides for ever.