Numbers 18:19

All the holy offerings that the Israelites present to the LORD I give to you and to your sons and daughters as a permanent statute. It is a permanent covenant of salt before the LORD for you and your offspring.”

All the heave offerings of the holy things, which the children of Israel offer unto the LORD, have I given thee, and thy sons and thy daughters with thee, by a statute for ever: it is a covenant of salt for ever before the LORD unto thee and to thy seed with thee.