Genesis 47:23-26

23Then Joseph said to the people, “Indeed I have bought you and your land this day for Pharaoh. Look, here is seed for you, and you shall sow the land.

24And it shall come to pass in the harvest that you shall give one-fifth to Pharaoh. Four-fifths shall be your own, as seed for the field and for your food, for those of your households and as food for your little ones.”

25So they said, “You have saved our lives; let us find favor in the sight of my lord, and we will be Pharaoh’s servants.”

26And Joseph made it a law over the land of Egypt to this day, that Pharaoh should have one-fifth, except for the land of the priests only, which did not become Pharaoh’s.