Catholics agree that "live forever" in these verses means salvation. This salvation is achieved through the literal eating of the bread of life - Our Lord. It is a necessary condition, though not a sufficient condition for salvation. Obviously other things are necessary for salvation besides partaking of the Eucharist - grace, baptism, faith, repentence, keeping the commandments, etc. Receiving the Eucharist and nothing else will not get one into Heaven - in fact if one is unrepentant and therefore receiving the Eucharist unworthily, his eternal destination might be quite the opposite (see 1st Corinthians).
is it achieved by symbolically appropriating "All" of Jesus (nature, blood, and flesh) through true belief in Him?
I'm not quite sure what you mean here. Are you trying to say that by belief in Jesus, we "eat" and "drink" his body and blood? Catholics believe that there is a distinction between believing in Christ and receiving the Eucharist. Both are essential for salvation, but they aren't the same thing. One doesn't "eat" the flesh of Christ in any other way but through the Eucharist. His flesh is "true food."
"63 The Spirit gives life; the flesh counts for nothing. The words I have spoken to you are Spirit and they are life.
It seems to me that He is focusing on the truth of the Word and not on the mechanical ingestion of food and drink. In any event, I think I see the argument more clearly now so thank you again.
"Flesh" in verse 63 doesn't refer to Christ's flesh. This is flesh that counts for nothing. Who could say that the flesh of Christ counts for nothing? Christ gave up His body on the cross for our salvation, so His body (i.e. His flesh) is very important. Furthermore, Christ has just commanded His disciples to eat his flesh. It would be very odd if Jesus was basically saying "You must eat my flesh for eternal life, but flesh counts for nothing."
Instead, the flesh in "flesh profits nothing" refers to human flesh. It refers to our inclination to think using only what natural human reason can tell us. Often Christians use the term "carnal" (literally meaning "fleshly") to describe this attitude.
Basically Jesus is saying that using your own human capabilities you cannot believe in this. Many people in the crowd that day did act carnally and left Christ. But through God's grace, one can follow Jesus whose words are spirit and life. One can believe the "hard teaching" of the Eucharist (as well as the many other hard teachings of Our Lord). And through that, one can have eternal life.
Hope this helps!
Wow! That is a hugh statement. I'm a Southern Baptist and we believe that Baptism has nothing to do with salvation. (How ironic :) Do Catholics really hold that keeping the commandments is necessary for salvation? Isn't that living under the old law? What is the Catholic view of the meaning of the new covenant?
Are you trying to say that by belief in Jesus, we "eat" and "drink" his body and blood?
Yes, that is fair enough. The level of appropriation grows through sanctification, and we remind ourselves of the importance of the sacrifice Jesus made for us by taking the Lord's Supper.
I agree with your assessment that verse 63 "flesh" was referring to weak human flesh. I was unclear in my point that Jesus was speaking of his Word(s) being actual life, as opposed to any action taken by human flesh.