People were not to consume blood because "the life" or "the soul" (Hebrew nephesh) of the animal is in the blood. As Leviticus states, "It is the blood that makes atonement, by the power of its life." While scholars continue to debate exactly what this means, one thing is clear: in the ancient world, the Jewish people were known for their refusal to consume blood.

For, as any ancient Jew would have known, the Passover sacrifice was not completed by the death of the lamb, but by eating its flesh. Five times the Bible states that they must "eat" the lamb; five times it emphasizes the sacrificial meal. The Passover was not completed by the death of the victim, but by a "communion" of sorts--by eating the flesh of the sacrifice that had been killed on your behalf.

Some ancient rabbis believed that the manna was protological--that it had existedsince the very dawn of creation. As such, the manna was the perfect food, untouched by the sin of humanity's first parents [...] the manna of the exodus was not just one more miracle but a kind of "return to Eden," a return to the state of creation before its corruption by sin and death.

The whole context of Jesus' bread of life discourse is centered on the Jewish hopes for the coming of a new Moses and the return of the manna from heaven.