פּירוש אויף ויקרא 17:11

“For the life of the flesh is in the blood” [17:11]. Ramban writes that the prohibition is because it was supposed to be sprinkled on the altar, just like the fat, which is forbidden because it was brought on the altar. Another explanation why blood is forbidden is because it is the soul of the person and the animal. The Holy One did not tell us to eat any soul, but only the body of the animal. We must have a clear mind to study Torah and if we would eat the blood of an animal we might have a base body like the animal, and also an uncompassionate body like the animals that engage in attacking and killing. Blood is not like other food that becomes digested in the body. It always remains blood, even when the person ingests it in his body. Rambam writes that blood is forbidden to eat because it was the custom of the Egyptians to be completely magical, and follow demons. They dug a pit and poured blood into it and the demons would gather around the pit. Later, whichever person drank from the pit, he would know what would happen in the future. Therefore, the Holy One forbade the eating of blood, expecting that they should not do magic.¹¹Bahya, Leviticus, 17:11. Bahya quotes both Ramban and Rambam.

כי נפש הבשר FOR THE LIFE OF THE FLESH of every creature, not only of animals brought as sacrifices, is dependent on its blood (בדם היא), and it is for this reason that I have placed it [on the altar] to make expiation for the life of man: let life come and expiate for life!

atones with the soul The blood secures atonement by means of the animal spirit which it formerly contained (in the sense of “a soul for a soul” [Exodus 21:23]). Other people interpret atones with the soul as a reference to the human soul, as in, to atone for your lives [literally: for your souls]. This interpretation is senseless, because it would make the verse redundant.