Numbers 18:19 (BSB)

All the holy offerings that the Israelites present to the LORD I give to you and to your sons and daughters as a permanent statute. It is a permanent covenant of salt before the LORD for you and your offspring.”

From Numbers 18. Also in the ESV.

Commentary on Numbers 18:19

• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Numbers 18:8-19: The priest's service is called a warfare; and who goes a warfare at his own charges? As they were well employed, so they were well provided for, and well paid. None shall serve God for nought. All believers are spiritual priests, and God has promised to take care of them; they shall dwell in the land, and verily they shall be fed, and shall not want any good thing.
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Numbers 18:19: And the Lord spake unto Aaron,.... What is said, being what concerned the tribe of Levi, at the head of which Aaron was, even concerning the maintenance of the Levites: thou shalt have no inheritance in their land; in the land of Israel when they come to possess it, as the rest of the tribes had: neither shalt thou have any part among them; any...
• Jamieson-Fausset-Brown (Reformed), Commentary Critical and Explanatory on the Whole Bible on Numbers 18:8-20: THE PRIESTS' PORTION. (Num 18:8-20) the Lord spake unto Aaron, Behold, I also have given thee the charge of my heave offerings--A recapitulation is made in this passage of certain perquisites specially appropriated to the maintenance of the priests. They were parts of the votive and freewill offerings, including both meat and bread, wine and oil, and the first-fruits, which formed a large and valuable item.
• Jamieson-Fausset-Brown (Reformed), Commentary Critical and Explanatory on the Whole Bible on Numbers 18:19: it is a covenant of salt--that is, a perpetual ordinance. This figurative form of expression was evidently founded on the conservative property of salt, which keeps meat from corruption; and hence it became an emblem of inviolability and permanence. It is a common phrase among Oriental people, who consider the eating of salt a pledge of fidelity, binding them in a covenant of friendship.