But if the Eucharist were as central to Christian life and belief as the RCC contends, and if the RCC reportedly chose all of the books that went into Scripture, why are the New Testament writings so completely devoid of mention of this practice and the importance of implementing it?
The text that you mention in which Christ calls himself the True Manna from Heaven proves nothing of the truth of transubstantiation. If that were the case, then anyone who eats of the Eucharist only once would "never hunger" again - would never have need of consuming the bread and wine a second time. But the RCC REQUIRES that the Mass be celebrated again and again and that communion is necessary again and again to accumulate grace - not for as yet uninitiated converts, but for existing adherents, even if they had taken communion a thousand times before. It can never be enough. So, what Christ meant by being Manna had to have been a spiritual metaphor, no less real than the eating of bread, but permanently effective in a one-time act of obedience.
Paul wrote to the Corinthians: "The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ?" (1 Cor. 10:16). So when we receive Communion, we actually participate in the body and blood of Christ, not just eat symbols of them. Paul also said, "Therefore whoever eats the bread and drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord. . . . For any one who eats and drinks without discerning the body, eats and drinks judgment on himself" (1 Cor. 11:27, 29). "To answer for the body and blood" of someone meant to be guilty of a crime as serious as homicide. How could eating mere bread and wine "unworthily" be so serious? Paul’s comment makes sense only if the bread and wine became the real body and blood of Christ.
Is the Bible the sole "teaching from God?" No. The Bible Itself states that their are "oral" teachings and traditions that are to be carried on to the present-day (2 Thessalonians 2:15; 1 Corinthians 11:2; 2 Timothy 2:2; Romans 10:17; 1 Peter 1:24-25). These teachings are what the Catholic Church considers "Sacred Apostolic Tradition." This type of "Tradition" never changes because it was passed down by the Apostles themselves. It is not the same as the man-made traditions condemned in Scripture. The man-made traditions condemned in Scripture were those of the Jewish Pharisees. In fact, as Christians, we are suppose to disassociate ourselves from persons who do not follow Apostolic Tradition (2 Thessalonians 3:6). If oral tradition is not to be followed, why did St. Paul state Christ said something that is not recorded in the Gospels (Acts 20:35)? St. Paul must have "heard" this saying, not read it from any Gospel or "Scripture," thereby, proving that some things Christ said were not recorded in the Gospels (John 21:25) and were passed on orally among His disciples instead, but were just as valid as anything written since St. Paul himself used one of these oral passages in one of his own epistles.
“I know of no biblical Protestant body that does NOT practice communion, very much the way Christ demonstrated it’.
You mean that maybe once a year bottle of grape juice and loaf of bread the good pastor brings to church and gives a few in the front role?
I was a Southern Baptist for 58 years and please do not insult my intelligence by telling me that that all protestant faiths participate in Holy Communion. The few protestant faiths that have held to some of Catholic doctrine, like the Lutherans, Episcopalians and Methodists, are the only protestant faiths that incorporate their version of communion as a weekly part of their services. The Jimmy Swaggart types, forget about it. It aint happening.