Only the land of the priests he bought not because they had considered him innocent at the time when his master was seeking to put him to death, and they had delivered him from the judgment of death: and besides he had said that a portion should be given them from Pharoh. So they ate the portion which Pharoh gave them, and sold not their land.
Why Joseph Spared the Lands of the Egyptian Priests
Targum Pseudo-Jonathan on Genesis 47:22