Or HaChaim on Deuteronomy 18:1/אור החיים על דברים י״ח:א׳

1 לא יהיה לבהנים…חלק ונחלה, "The priests shall not have a portion and an inheritance, etc." Why did the Torah repeat the word נחלה, "inheritance" in our verse? The reason may be to tell us that if some priests ignored the law and acquired land and used it as an inheritance, such an inheritance is legally invalid. This may be why the Torah phrases it ונחלה לא יהיה לו in verse two, i.e. he will not be allowed to hang on to such an inheritance. The reason this commandment follows on the heels of the legis lation to appoint a king is to tell you that the king is equal to the common people when it comes to giving the priests their due. He is not exempt from the 24 different kinds of gifts the priests are entitled to from the Israelites. "He must not raise his heart," i.e. think that he is above the law in this respect.