Bible Verses About Salt: Ratifying covenants

all the heave-offerings of the holy things which the sons of Israel lift up to Jehovah I have given to thee and to thy sons, and to thy daughters with thee, by a statute age-during, a covenant of salt, age-during it is before Jehovah, to thee and to thy seed with thee.'

Is it not for you to know that Jehovah, God of Israel, hath given the kingdom to David over Israel to the age, to him and to his sons--a covenant of salt?