Deuteronomy 15:1, 12-15, 18

“At the end of every seven years you shall grant a release.

“If your brother, a Hebrew man or a Hebrew woman, is sold to you, he shall serve you six years, and in the seventh year you shall let him go free from you. And when you let him go free from you, you shall not let him go empty-handed. You shall furnish him liberally out of your flock, out of your threshing floor, and out of your winepress. As the LORD your God has blessed you, you shall give to him. You shall remember that you were a slave in the land of Egypt, and the LORD your God redeemed you; therefore I command you this today.

It shall not seem hard to you when you let him go free from you, for at half the cost of a hired worker he has served you six years. So the LORD your God will bless you in all that you do.