This is my point exactly, it is the foundations of the Catholic Church that laid out the New Testament as we know it today, yet the teachings are followed/reject haphazard. How can you claim Peter to be the first pope and to be descendants of the Apostolic Church and not follow its teachings which are outlined in the New Testament, which you helped compile!?
Because the authority reposes in God, who lives in the Church, and the Scriptures are a written record of what God said and did in that time, to teach and inspire us. What they are NOT is a new set of stone tablets. It is a history book, the story of Christ coming into the world and beginning the process of leading each successive generation to God. Jesus and the Apostles were facing a Jewish world with specifically Jewish issues. Much of the particular language in the Scriptures, both of Jesus and of the Apostles in their various letters, are addressed to Jewish questions, and Jewish theological concerns under the Jewish Law. But Christianity spread across the world among the Gentiles, who were never under the Jewish Law in the first place, and who were not BROUGHT under it by Jesus. Jesus had a New Covenant that was not a repouring of old wine into new bottles, nor new wine into old bottles. Ecclesiastes was wrong: there ARE new things under the Sun, and Jesus' covenant was one of those.
Jesus' covenant was not bound to a book or a law, but to God, and the Holy Spirit was to lead it. He breathed the Holy Spirit into Apostles, the head of the Church he founded, and sent the Holy Spirit into the Church, to lead it forward.
The Apostles dealt with Jews, and with the Greco-Roman edge of paganism. But as the Church spread, it encountered all sorts of new beliefs, conditions, gods, foods, customs, on different continents and in different ages.
The Church, the Holy Spirit, are not bound to the answers given to the Jews in response to different questions in different times. Rather, God continued to send his revelations, his messages, his messengers (such as Joan of Arc, or the Virgin Mary) to different times and places and conditions. God speaks to the Church. Jesus planted a seed in the Apostles, and the Apostles sprouted out and wrote the first texts recording what Jesus said and did, and keeping track of what God had done for the Jews before that. But the Church flowered, grew, and spread, and as it did, God showed new things. For example: the old Jewish law prohibition on the eating of blood was set aside in order to accomodate people in lands such as Scandinavia and East Africa where blood is a staple. Jesus said NOTHING a man puts in his mouth makes him unclean and made ALL foods clean. The very Jewish apostles still could not stand the thought of eating blood, so the Council of Jerusalem made abstaining from blood one of the terms of the early Jewish-Christian faith.
However, the Holy Spirit later, in the Middle Ages, set this aside. The blood-sausage eaters of the North - Germans, Scandinavians, Saami, and the blood of the African East - the Masai eat blood as a staple. So, is not eating blood a fundamental requirement of salvation? Or did Jesus really mean it when he said that NOTHING that went into a man's mouth made him unclean?
Who can say? Who can resolve that jump ball? The answer is God. And God reposes in the Church, as the Holy Spirit. God DID answer the question, and the Church made it clear that the eating of meals made with blood is NOT a sin for followers of Christ. And that is that. God spoke through the Church and ended what would otherwise be an endless (and fruitless) debate.
We see in the Acts of the Apostles the bishops and leader of the early Church already exercising their authority to decide through the guidance of the Holy Spirit. The Holy Spirit remains as present in the Church today, to the Pope and cardinals, as it was to the Apostles. Francis and the archbishops of the Church occupy the same office as Peter and the Apostles, and exercise the same undecayed authority for the same reason: the Holy Spirit dwells in the Church and guides them just exactly as it did Peter. And just as God's message evolved from Adam through Cain and Abel, Noah, Abraham, Moses, Jesus, and then the First Century Apostles, it continues to do so, guided by God, through His Church.
Your doctrine would limit revelation to what was written in the First Century, but this is arbitrary. Catholics believe that the Holy Spirit still dwells in the Church and guides it every day, until the end of time.