Although we read the Gospels before reaching the writings of Paul, the reality is that Paul wrote his 7 letters at least 10 years before the earliest Gospel, by "Mark" (who was not a disciple). Why is this important in the context of the "memorial"?
Because it is Paul who first wrote that Jesus said "this is my blood, drink it". Paul was not there. Paul was estranged from the community at Jerusalem, keeping away from them for 3 years, and then only having short private meetings. Paul explicitly states that he did not receive information from any man, only directly from Jesus Christ.
Where did Paul find out that Jesus said these words? He received them in a visionary contact with the dead and resurrected Jesus. The later writers simply copied Paul. That's the reason the words are so similar. Paul got the words while he was on a "high", in an other-worldly state.
And would a Jew really say "drink my blood"? Did Jesus say he was going to drink his blood with his disciples when they are in the kingdom?
Black Mass. White Mass. Red Mass. Green Mass.
It's all the same - it all came from one man's imagination.
Doug