Among the claims made by people seeking to assert that Jesus was just a knock off of Pagan mystery cults is sometimes a claim that The Last Supper must have come from the Mystery cults, probably a Dionysus/Bacchus one in that case. Though there is also a ritual meal associated with Mithras people talk about.
I'm not gonna even bother with evidence for similar rituals existing among the Mystery Cults, cause no one ever claimed drinking wine and eating bread in a religious ritual must be some completely unique idea. I just want to show the Torah and TNAK precedent for various aspects of it.
I do believe that The Last Supper was NOT a Passover Seder, I believe the Lambs for the Passover were slain while Jesus was on The Cross. But regardless it is firmly rooted in The Hebrew Bible.
The idea of a supper involving Bread and Wine is introduced in Genesis 14, the supper Melchizedek holds for Abraham. Melchizedek is refereed to as a Type of Christ in Hebrews, and Jesus Himself quoted Psalm 110 in Matthew 22.
Wine is refereed to as the "Blood of Grapes" in Genesis 49:11 and the "Prue Blood of The Grape" in Deuteronomy 32:14. Also see Isaiah 49:26 and 63:3, imagery that is drawn on in Revelation 14:20. There are two Hebrew words translated Blood, Dam Strong Number 1818 and Netsach Strong Number 5332. According to the Strongs Concordance, both of them are linked to Wine in their very etymology.
When Jesus took the Cup at The Last Supper, He paraphrased not part of the Passover account but Exodus 24:8.
The only piece of this puzzle I can't think of a solid Old Testament precedent for is Bread representing the Body. Maybe Genesis 3:19 could help explain it. But the Wine part is the primary basis for seeing it as based on a Dionysian ritual.
Update: Here's a follow up post I did tying the Showbread into it.
