The phrase "covenant of salt" is a biblical reference to a symbolic agreement or binding contract made between two parties. Other synonyms that can be used for this phrase include pledge, promise, deal, agreement, alliance, compact, and contract. These words represent the same idea of a mutually beneficial agreement between two parties, whether it be in business or a personal relationship. The phrase "covenant of salt" comes from the practice in ancient times of using salt as a preservative in food and as a symbol of lasting friendship and loyalty. The use of such phrases helps to convey the strength and depth of a commitment made between two parties.