'Covenant of Salt' in the Bible

All the offerings of the holy things, which the Israelites offer to the Lord I have given to you and to your sons and your daughters with you as a continual allotment. It is an everlasting covenant of salt [that cannot be dissolved or violated] before the Lord to you and to your descendants with you.”

Do you not know that the Lord God of Israel, gave rule over Israel forever to David and to his sons by a covenant of salt [a permanent pact, extending to each generation of Israel]?