The pollution in the priests would be an aggravated one, inasmuch as they would have to forego their sacred functions. Compare Ezekiel 4:14; Ezekiel 44:31. The general prohibition occurs in Leviticus 11:39; Leviticus 17:15; Exodus 22:31.

That which dieth of itself, or is torn with beasts,.... Whether fowls or beasts, and even clean ones, which, had they been killed in a proper manner, were fit to cut, but dying of themselves, or torn to pieces by other birds or beasts of prey, might not, see Ezekiel 44:31,
he shall not eat, to defile himself therewith; being impure food, at least in a ceremonial sense, and not fit to be eaten; these things were forbid a common Israelite, and much less might a priest eat of them, see Leviticus 17:15,
I am the Lord; who enjoin this, and expect to be obeyed.

dieth of itself--The feelings of nature revolt against such food. It might have been left to the discretion of the Hebrews, who it may be supposed (like the people of all civilized nations) would have abstained from the use of it without any positive interdict. But an express precept was necessary to show them that whatever died naturally or from disease, was prohibited to them by the operation of that law which forbade them the use of any meat with its blood.