Torah forbids eating blood in 8 places. In one place the reason is given: the redemption is in blood. In another place not only eating blood is forbidden, many aspects of practical Kabbalah are forbidden, yet practical Kabbalah was performed by Ba’al Shems. (It was also forbidden to pronounce the name of God, but Ba’al Shems did it. Pronouncing the name gave power, just like blood gave power. It was forbidden for ordinary Jews, but not for Ba’al Shems.)
Thus, there were two reasons for the ritual sacrifice of Christian children: for the redemption of the people and for powerful magic requiring the assistance of God. Yes, though they themselves cheated, they did believe that in magic in the name of God would work.
Thomas in his description of William of Norwich tells what a converted Jew Theobald of Cambridge explained to him: the Jews believed that they had to sacrifice a Christian boy every year because otherwise they could not return to their country. This is just saying that the Jews could not return to Israel before redemption and that the redemption is in blood.
The corresponding place in the Babylonian Talmud is Sanhedrin 43a. In plain language it says that killing disciple of Jesus in a covert place is to honor God as by a sacrifice of the innocent firstborn. The body cannot be buried but must be through away, as was always done in suspected Jewish ritual murders.
The text Sanhedrin 43a is as follows: “There is a tradition: Yeshu had five disciples —Mathai, Nakkai, Netzer, Bunni, Todah. Mathai was brought before the judgment seat. He said to the judges: Is Mathai to be put to death? Yet it is written: Mathai ( = when) shall I come and appear before God ?, They answered him: Nay, but Mathai is to be executed; for it is said: Mathai (when) shall (he) die and his name perish?. Nakkai was brought. He said to them: Is Nakkai to be put to death? Yet it is written: Naki (=the innocent) and righteous slay thou not. They replied to him: Nay, but Nakki is to be put to death; for it is written: In covert places doth he put to death the Naki. Netzer was brought. He said to them: Is Netzer to be put to death? Yet it is written: A Netzer (branch) shall spring up out of his roots. They answered him: Netzer is to be put to death; for it is said: Thou art east forth from thy sepulchre, like an abominable Netzer. Bunni was brought. He said: Is Bunni to be put to death? Yet it is written: Israel is Beni (my son), my first born. They answered him: Nay, but Bunni is to be put to death; for it is written: Behold, I will slay Binkha (thy son), thy first born. Todah was brought. He said to them: Is Todah to be put to death? Yet it is written: A psalm for Todah (thanksgiving). They answered him: Nay, but Todah is to be put to death; for it is written: Whoso offereth Todah honoureth me [Ps. i.23].” Read this as many times as you need to understand it.
This place in Talmud does not demand drinking blood, but as Jesus told his disciples to drink his blood and eat his flesh for redemption, we can be sure that this was the correct tradition of Second temple Judaism and it lasted in Kabbalism.
The magical usage of blood can be found from Jewish magical and kabbalistic books. A sacrifice is necessary for higher magic since it requires approaching God and Torah forbids approaching God empty-handed. Sefer HaRazim tells to make cakes from flour and blood of a lion cub. These cakes are not eaten, they are used for magic, just like in the Hagganah ritual Toaff tells about wine with blood is not drunken, it is poured to the ground, as Torah tells to do. The blood is needed for casting spells.
We find a command for drinking blood from the most holy book of Zohar: Idra Zuta in the end tells the whole companion to drink blood. Before that Idra Zuta tells twice that a sacrifice is necessary to calm the hatred of the lower God (microprosopus). What can the blood that the companion is commanded to drink be? If cannot be blood of the children of the Promised People, as that is forbidden, the children must be redeemed. It cannot be animal blood, as prophets say God does not want your animal sacrifices. The only blood that can be used is human but not from their people.
Blood would not be consumed in magical usage of blood. It would be far too dangerous, as the soul was believed to be in blood and the punishment of eating blood was death. I try to explain the concept of eating blood in Second temple Judaism.
A good starting point is the saying of Jesus in logion 7 in the Gospel of Thomas. ‘Jesus said, “Blessed is the lion that the human being will devour so that the lion becomes human. And cursed is the human being that the lion devours; and the lion will become human.’
There are many strange misunderstandings of these words: Gnostics thought that the lion means something evil, while Didymos the Blind thought that eating means accepting somebody’s teaching and that the ending should be that the human will become lion, but it is not so. The logion is meant just as it is above in the context of 1st century Judaism.
The most logical explanation for this logion is that it talks about eating blood. Corpses can be eaten and they are destroyed when eaten, but blood is alive and has the soul. Thus, by eating blood you take the soul in the blood to your soul. If a lion devours a human, the lion gets the soul of the human, and according to Jesus this is bad: the human is cursed. While if a human devours a lion, the human stays as a human. Why so? It is because lion means here a human, not the animal. The lion is the king of Israel, the Messiah, a human with a pure soul. If a human eats blood containing the pure soul, he will become a human with a pure soul. The source of the pure soul, the lion, is blessed. While if the lion, the Messiah, eats blood that contains a human, impure, soul, he will become human with an impure soul. The source of the blood is cursed, as he destroyed the pure soul, not because he would be cursed by getting to the body of the Messiah.
The message of this logion is that only blood with a pure soul can be eaten. Redemption is in blood, but only in the blood of the Messiah.
Let us return to the cakes of Sefer HaRazim, the blood there must be from a cub of a lion. Jews of the 3rd century were not known to be hunting lions. This blood is not from a real lion: again the lion means the Messiah. The cub of a lion is a disciple of the Messiah, but it is very risky to drink blood from a disciple. He most probably does not have a pure soul. For magic such blood can be used, it may still work if the soul was pure, but drinking it is at a too great risk. It is better to break the cakes for predicting the future.
Whoever ate blood had to die, but if he ate the pure soul, he would live as he ate life. He would be resurrected. Christians solved this problem by drinking blood in a symbolic way as wine, while high priests in the Day of Atonment took made two very dangerous things: they pronounced the forbidden name and ate drops of blood for redemption of the people’s sins. Jesus of course made miracles with God’s power and had to use the forbidden name.
Each Kabbalistic Ba’al Shem could have been the promised Messiah (they had a secret society called Nistarim), and therefore there is the command for the whole companion to drink blood, but the Rabbi who so recommends was raised to the Heaven, had died as the punishment is death. This is in Idra Zuta, which is not in Zohar proper but in the extended Zohar. I would imagine that the whole companion drank blood, died and were raised to Heaven. There is also the Kabbalistic Tipheret rite, which may be related. It seems to have had a ritual murder as the main component, but the information is meager.
For those of us, like me, who like their beef steaks bloody, this Jewish concept of blood may be somewhat strange. It is a very complicated issue, but it is something like this. For students of the true meaning of the words of Jesus this issue is important. I strongly suspect that what Jesus meant was not how it is now understood in Christianity. Just read the ending of the book of Zechariah, which has in the Deutero Zechariah so many places reminding of Jesus and the ending is just the same Jewish supremacy idea.