Yes I realize that, but that's not how it is preseneted in the Gospels and the catholic and apostolic Church is based on the Gospels.
Well, first of all, the "Gospels" - Matthew, Mark, Luke and John - are full of references, most from Jesus' own mouth, that he is the Christ, the Messiah, the Chosen One. He repeatedly refers to Moses and the Prophets speaking of him and the whole purpose of his coming. If he was not the "Lamb of God who takes away the sins of the world", then who was he? What was the point of his death on the cross if not for taking on the sins of the world? His shed blood was for the propitiation of our sins and was the once and for all sacrifice that all the sacrifices in the temple pointed to. They were only a covering until he came and took away our sins, nailing them to the cross.
Secondly, it is startling that you imply Catholics and Orthodox only base their doctrines upon the first four books of the New Testament. Should we all just toss out the rest of the Bible? I seem to think our Lord would not be too pleased if we did. The Holy Spirit went to all that trouble for nothing???