Numbers 18:19

“All the heave offerings of the holy things, etc.] All before mentioned, and whatsoever comes under that name: which the children of Israel offer unto the Lord; either by his commandment, or of their own freewill; have I given thee, and thy sons, and thy daughters with thee, by a statute for ever: so providing for their maintenance by an irrepealable law as long as their priesthood lasted, even until the Messiah should come: it [is] a covenant of salt for ever before the Lord unto thee, and thy seed with thee: an incorruptible, inviolable, durable covenant, which should last for ever, even until the Gospel dispensation or world to come should take place; and it would remain ever before the…”

“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. Hence the partaking of the altar meats, which were appropriated to the priests on condition of their services and of which salt formed a necessary accompaniment, was naturally called "a covenant of salt" (Lev 2:13).”

“A covenant of salt - Compare the marginal reference. covenants were ordinarily cemented in the East by the rites of hospitality; of which salt was the obvious token, entering as it does into every article of diet. It indicates perpetuity: compare Leviticus 2:13 note. return to 'Top of Page'”

“A covenant of salt - A durable and perpetual covenant; so called here and Ch2 13:5, either, because salt is a sign of incorruption, as being of singular use to preserve things from corruption: or, because it is ratified on their part by salt, which is therefore called the salt of the covenant, for which the priests were obliged to take care, that it should never be lacking from any meat - offering, Lev 2:13. And this privilege conferred upon the priests is called a covenant because it is given them conditionally, upon condition of their service, and care about the worship of God. Numbers 18:20”

“18:19 These arrangements were part of an eternal and unbreakable covenant (literally a covenant of salt; cp. 2 Chr 13:5). The covenant was apparently meant to be permanent, since salt (a preservative) was a symbol of permanence (Lev 2:13).”

“the heave: Num 18:8, Num 18:11, Num 15:19-21, Num 31:29, Num 31:41; Lev 7:14; Deu 12:6; Ch2 31:4 it is a: Lev 2:13; Ch2 13:5 Numbers 18:20”

“"All the holy heave-offerings" are not the thank-offerings (Knobel), but, as in Num 18:8, all the holy gifts enumerated in Num 18:9-18. Jehovah gives these to the priests as an eternal claim. "An eternal covenant of salt is this before Jehovah," for Aaron and his descendants. A "covenant of salt;" equivalent to an indissoluble covenant, or inviolable contract (see at Lev 2:13). Numbers 18:20”