I assume that it has roots in Pagan tradition. Of course I don't know for sure. Possibly a reform of what had once been actual cannibalism, as we know human sacrifice had been in the area historically. Jews had a prohibition against drinking blood, so Jesus never said, 'drink my blood.' References to 'your' celebrations in Jude 1:12 -- 'your love feasts.' The Pagans had celebrations of the 'sacred marriage' with real sex, recalling the sacrificial death of the young lord whose blood was beneficial; for example, fertilizing the soil (in many mythological stories), with the lady, his incestuous mother/bride weeping over his death. In the earliest stories, she kills him. This horror was continued in the Roman Catholic tradition of Mary Priest who presided over his crucifixion, a belief finally banned by Rome. In the Hebrew Bible, is this Pagan ritual like imprinted hosts and cup? "We were making cakes impressed with her image and pouring out drink offerings to her” Jer 44:17-19 continuing