It is a covenant of salt— That is, a perpetual covenant, or one which should last as long as that dispensation should last; see Leviticus 2:13. The reason of this mode of expression seems to arise from the preserving nature of salt; which, therefore, most probably, was held a symbol of friendship and fidelity. Hence the Greek proverb, αλα και τραπεζαν μη παραβαινειν, not to violate the salt and the table; i.e. the laws of friendship and hospitality. It is most likely, that in all solemn covenants which were confirmed by sacrifice, it was an ancient custom to offer salt with the sacrifice, to denote the faith and perpetuity of the covenant; so that, in this view, a covenant of salt will signify a covenant confirmed by sacrifice. It is well known, that the heathens were careful also to offer salt with all their sacrifices; a custom, most probably, derived from the very beginning of the world, and the first sacrifices which were offered; see Spencer, p. 760, and Calmet on the place. The Turks, to this very day, say of those who have entered into a vow of perpetual friendship, that they have eaten salt together; see Adag. Erasmi, under the words Sal and Mensa. Mr. Locke says, it is called a covenant of salt, because covenants were established by eating and drinking together, where salt was a necessary appendage.
REFLECTIONS.—God will have his servants liberally provided for: they shall not serve him for nought. As by their service they were excluded from all means of gain, the altar they served supplied them with plenty, and of the best. The offerings and first-fruits provided meat and drink for their families; and the ransom-money, and things dedicated, supplied them with every other necessary. Note; (1.) They who serve at the altar should live by the altar. (2.) A godly people will make a liberal provision for a gospel ministry. (3.) They who have the care of souls need have no other care upon them. (4.) Let faithful ministers trust their families with God; as he has provided for them while they live, he will not forget them when they are dead.