Albert Barnes Commentary Deuteronomy 18:1

"The priests the Levites, [even] all the tribe of Levi, shall have no portion nor inheritance with Israel: they shall eat the offerings of Jehovah made by fire, and his inheritance." — Deuteronomy 18:1 (ASV)

Better, “there shall not be for the priests, the Levites, even the whole tribe of Levi, any inheritance, and so on.”

And his inheritance – that is, God’s inheritance, what in making a grant to His people of the promised land with its earthly blessings He had reserved for Himself; more specifically, the sacrifices and the holy gifts, such as tithes and first-fruits.

These were God’s portion of the possessions of Israel; and as the Levites were His portion of the people of Israel, it was fitting that the Levites should be sustained from these. Concerning the principle set forth here, compare (1 Corinthians 9:13–14).