We are told by Moshe to get rid of all idols and traces of idols in the land G-d gave us Israel. “Moses instructed the Jewish people to eradicate all traces of idolatry from the Land of Israel. He then instructed them to establish a centralized location for the sacrificial rites (which would eventually become the Temple in the city of Jerusalem). He then informed them that although the blood of the sacrifices is “consumed” by G‑d on the Altar, animal blood should not be consumed when they eat meat themselves.”
[Moses told the Jewish people that when they eat meat, they must] “be resolute not to consume the blood.” Deuteronomy 12:23
Inasmuch as the blood of an animal embodies its vitality, it might seem that consuming blood in order to utilize this vitality for holy purposes would actually be a praiseworthy effort to refine the material world. It is therefore necessary to distinguish between meat and its blood. Meat signifies the material world itself, which we are capable of enjoying in a holy way. Blood, however, signifying the vitality and enthusiasm of life, cannot be enjoyed itself, for it is impossible to enjoy pure enjoyment in a selfless, holy way.
Thus, blood may be offered up on the Altar as part of a sacrifice, for then it is oriented solely toward holiness. But if it is part of the simple act of eating, oriented merely toward preserving and enhancing the life of the body itself, it must be avoided. We should aspire to become excited and enthusiastic solely about holy matters, rather than about material matters in and of themselves.1Likutei Sichot, vol. 4, p. 1110; ibid., vol