And Joseph made it a law over the land of Egypt unto this
With the consent of Pharaoh, his nobles, and all the people of the land, who readily came into it; and so it became, a fundamental law of their constitution, and which continued to the times of Moses, the writer of this history:
[that] Pharaoh should have the fifth [part];
that is, of the increase the whole land of Egypt produced:
except the land of the priests only, [which] became not Pharaoh's;
it not being bought by him; so Diodorus Siculus F13, as he assigns the first part of the land to the priests, so he says they were free from all taxes and tribute, and next to the king were possessed of honour and authority.
F13 Ut supra. (Bibliothec. l. 1. p. 47.)