Ah…the Eucharist. I admit, I did not read much of the posts you referenced, but I was involved in a Transubstantiation thread recently and want to give you my logic, then refer you to some great reading on the subject!
I think John 6 is quite clear. Jesus explicitly said that you had to eat His flesh and drink His blood. Some of His disciples found this revolting and bolted, without a word of protest from Jesus. (He laments a little, even asking the Twelve if they’d like to leave too, but He never makes any attempt to disuade the deserters) Now, why would the Savior, after having given the words of eternal life(!) not clarify right there that He was being poetic. He did so during other discourses and parables that caused mere confusion, not even desertion.
So from that incident, you would have to believe that Jesus did not care for the souls that left Him that day IF He were to let them go over a mere misinterpretation. That is impossible, because God loves us and wants us to be with Him. This does not mean that we do not have free will, we are free to believe the words of eternal life, or not. So the seriousness of the discourse and the fact that Jesus just lets them go is evidence that John 6 55&56 are to be taken literally, because Jesus did when he spoke them.
As for Paul, he mentions that anyone taking the bread or the cup unworthily is GUILTY of the body and blood of Jesus. So if you take the Eucharist in a state of mortal sin, its as though you just pierced the side of Christ. Sounds like Paul took the Eucharist pretty seriously, too. That’s not just some blessed pita and a little tipple, that is the Body and Bood of Our Lord Jesus Christ, remaining with us until the very end of time.
Now, as I am not a theologian, I am going to reccommend my favorite (other than Pope Benedict XI). Scott Hahn’s book Rome Sweet Home brought me back to the Church of my youth. It is the story of a serious antiCatholic who, through study, logic and reason, completely turns his life upside down to become Catholic. What got me was not just his faith, but the scriptural references that he uses and the logical progression of his conversion. It is awesome.
catholic.com/thisrock/1991/9109fea1.asp
This article by Scott Hahn is also a great piece on why it is important that eating the Body and Blood of Christ was part of Jesus’ sacrifice.
Good luck in your quest for Truth.
