Sefer HaChinuch ספר החינוך

To not offer a sacrifice without salt: To not omit salt from upon the sacrifice or upon the meal-offering; meaning to say that the priests not offer any sacrifice or any meal-offering unless they place salt in them, as it is stated (Leviticus 2:13), “you shall not omit the salt of your covenant with God from your meal-offering.” And it is also written (there), “upon all your offerings you shall offer salt.”

I have written from the roots of the commandment above at the beginning of the Order.

From the laws of the commandment is [that which] they, may their memory be blessed, said (Menachot 21a) that it is a commandment to salt the meat properly — similar to the salting of meat for roasting — such that he salts it from both sides. But it is fit, ex post facto, even if he salted it a tiny bit (Mishneh Torah, Laws of Things Forbidden on the Altar 5:11). And the salt with which we salt the sacrifices is the community’s, like the [fire]wood. And an individual does not bring salt or wood for the sacrifices. And all of this is from the aggrandizement of the [Temple]; as “in a place of wealth, there is no poverty” (Shabbat 102b). And they would put the salt in three places: in the chamber of salt; on top of the ramp; and at the top of the altar. They would salt the limbs in the chamber of salt, and they would salt the handful, the frankincense, the burnt meal-offerings and the burnt-offering of the fowl at the top of the altar. And the rest of its details are in the seventh chapter of Zevachim.

And [it] is practiced at the time of the [Temple] by the males of the priesthood, as it is for them to complete the requirements of the sacrifice. And a priest that transgresses and offers a sacrifice or meal-offering without salt at all, has violated a positive commandment and also violated this negative commandment. And he is lashed — as behold, there is an act here when he offers the bland meat, about which he has been warned not to offer it without salt.