Albert Barnes Commentary Leviticus 2:13

"And every oblation of thy meal-offering shalt thou season with salt; neither shalt thou suffer the salt of the covenant of thy God to be lacking from thy meal-offering: with all thine oblations thou shalt offer salt." — Leviticus 2:13 (ASV)

With all thine offerings thou shalt offer salt - Not only every מנחה mı̂nchāh — but every animal offering was to be accompanied by salt. It was the one symbol which was never absent from the altar of burnt-offering, showing the imperishability of the love of Yahweh for His people. In its unalterable nature, it is the contrary of leaven (yeast). The Arabs are said to retain in common use the expression, “a covenant of salt;” and the respect they pay to bread and salt in their rites of hospitality is well known.