Deuteronomy 12:23-24. Only be sure that thou eat not the blood: for the blood is the life; and thou mayest not eat the life with the flesh. Thou shalt not eat it; thou shalt pour it upon the earth as water.
See also Genesis 9:4; Leviticus 7:26-27; 17:10-14.
The discussion which has risen on the various reasons for this prohibition of blood for food, so far as it concerns the physical consequences of such diet, or the typical character of sacrificial blood, or the relation of the blood to the life, can have no place here. There are, however, reasons for the law which may have been drawn from ancient idolatrous and cruel customs to which we may with propriety refer. R. Moses Bar Nachman, an old Jewish writer, says that the Zabians “gathered together blood for the devils, their idol gods, and then came themselves and ate of that blood with them as being the devil’s guests, and invited to eat at the table of devils, and so were joined in federal society with them; and by this kind of communion with devils they were able to prophesy and foretell things to come.” (Townley's Maimonides, p. 76).
The sacred books of the Hindus exhibit traces of the same infernal mode of worship. They give directions concerning various oblations of blood, the different animals from which it may be drawn, and the different vessels in which it may be offered, positively forbidding, however, to pour it on the ground. If a similar prohibition existed among the Zabians, verse 24 may be a reference to it, commanding the Hebrews to do what the Zabians were forbidden. Hindu devotees drink the reeking blood from newly killed buffaloes and fowls.
“Drink offerings of blood” are spoken of in Psalm 16:4 and in Zechariah 9:7; there is evident allusion to the idolatrous use of blood.
In addition to this, the old Jewish rabbis say that this prohibition against blood was made on account of an ancient custom of eating raw flesh, especially the flesh of living animals cut or torn from them, and devoured while reeking with the warm blood. Bruce tells of a similar custom among the modern Abyssinians, and his statement, though at first received with ridicule, has been confirmed by other travelers. The hungry Israelites, after defeating the Philistines between Michmash and Aijalon, seem from the narrative in 1 Samuel 14:32-34, to have indulged in a similar horrid practice.