Rashi on Leviticus 2:13/רש"י על ויקרא ב׳:י״ג

1מלח ברית [NEITHER SHALT THOU SUFFER] THE SALT OF THE COVENANT [… TO BE LACKING FROM MY MEAL OFFERING], because a covenant was established with the salt as far back as the six days of Creation when the lower waters (those of the oceans) received an assurance that they would be offered on the altar in the form of salt and also as water in the ceremony of “the libation of water” on the Feast of Tabernacles).‎

2על כל קרבנך‎ UPON ALL THY OFFERINGS [THOU SHALT OFFER SALT] — upon burnt-offerings of cattle and fowls and upon the fat-portions of all sacrifices in general (Menachot 20a).