SALT, COVENANT OF. A covenant of permanent and perpetual obligation. Since salt is a necessary part of the daily diet, and salt was always used in sacrifices to the Lord (Lev.2.13), it was not long before people saw a connection between salt and covenant making. To “eat salt with” a person meant to share his hospitality. When covenants were made, they were usually confirmed with sacrificial meals, and salt was always present. Num.18.19 says that offerings to the Lord were to be “an everlasting covenant of salt before the Lord.”
COVENANT OF SALT
). An expression used in OT times for a perpetual covenant.
The ceremonial law called for the use of salt in all cereal offerings and perhaps in other offerings as well, according to the Mosaic instruction (Lev 2:13). Being a necessary part of human diet, it is not surprising that it should be included in the prescribed offerings to God. While some of these offerings were consumed on the altar, the greater part was for use by the priests, for they had no inheritance among their brethren by which to obtain food. Therefore, all the holy offerings which the people presented to God were given to the priests and their families “as a perpetual due; it is a covenant of salt for ever before the Lord for you [the priests] and your offspring with you” (Num 18:19). From this Levitical concept there evidently arose the expression among the Hebrews that any perpetual covenant is a covenant of salt. Jeroboam, the son of Nebat, who split Israel from the Davidic line is reminded by King Abijah that God gave the kingship to David and his sons by a covenant of salt, that is, forever (2 Chron 13:5).
International Standard Bible Encyclopedia (1915)
As salt was regarded as a necessary ingredient of the daily food, and so of all sacrifices offered to Yahweh (Le 2:13), it became an easy step to the very close connection between salt and covenant-making. When men ate together they became friends. Compare the Arabic expression, "There is salt between us"; "He has eaten of my salt," which means partaking of hospitality which cemented friendship; compare "eat the salt of the palace" (Ezr 4:14). Covenants were generally confirmed by sacrificial meals and salt was always present. Since, too, salt is a preservative, it would easily become symbolic of an enduring covenant. So offerings to Yahweh were to be by a statute forever, "a covenant of salt for ever before Yahweh" (Nu 18:19). David received his kingdom forever from Yahweh by a "covenant of salt" (2Ch 13:5). In the light of these conceptions the remark of our Lord becomes the more significant: "Have salt in yourselves, and be at peace one with another" (Mr 9:50).