While it is true the Catholics put the letters together and made them into a book which is the Bible.
The workers in an auto plant puts the cars together but are they any better drivers than any one else? and no way near as good as the old traveling salesman.
The Letters as you call them are the basis of the Liturgy of the Eucharist authored by St Justin Martyr around 128 AD
This is the wording of the Holy Mass the Eucharistic Celebration The ONLY Covenant of the New testament. The Body and Blood Soul & Divinity of Our Lord Jesus Christ who died for the atonement of our sins and those of the WHOLE WORLD!
Read In JOHN about the REal Presence in the Eucharist and what Jesus Christ told the Jews what would happen if they refused to Believe and Eat his Body and Drink his Blood.