Consider scenario: You are at park, minding your own business and enjoying a day off from your labors. Suddenly, he appears. The well-meaning Christian who wants to "save" you from damnation. In his zeal to enlighten your wretched soul, he whips out his handy Bible and fires off a few choice New Testament phrases. He is confident you will be dazzled.He begins by citing St. Paul in ever-popular 2 Tim 3:16, "All scripture is inspired by God and is useful for teaching, for refutation, for correction and for training in righteousness..." This is rapidly followed by Christ's admonition to Sadducees in Mt. 22:29, "...You are misled because you do not know scriptures or power of God." Finally, he clinches deal with story of learned Jew turned believer named Apollos who, in Acts 18:28, "...vigorously refuted Jews in public, establishing from scriptures that Messiah is Jesus."
He appears quite pleased with his efforts. Having shown you preeminence of scriptures in selected passages, he hopes you'll conclude, as he has, that Bible is all you need for salvation. No creed, no church, and no hierarchy are required.
Taking a long pull on your coffee, you look him square in eye. With devastating kindness, you thank him for honoring authority of Catholic Church. He stiffens up immediately. Like a dog looking at a clock, his facial expression belies a complete lack of understanding. He is momentarily silent, for he has no pithy rejoinder to such a bizarre comment.
He finally gathers his thoughts enough to inquire as to what your response could possibly mean. You politely declare that you are a Catholic and, as such, believe that fullness of Truth resides in Catholic Church, not simply in Bible. The Bible, you affirm, is part of a much larger deposit of revelation. In fact, Catholic Church is mother of Bible.
Shocked at your impunity, he immediately fires back that you are calling into question very Word of God, hoping that will cow you into submission. You smile and offer to share some insights to defend your position. He agrees to listen, half-expecting to be amused as you concoct some wild story.
You begin by explaining that New Testament letters and accounts he cited earlier of Paul, Matthew, and Luke (author of Acts) were written during first century. While Christianity survived underground during ensuing centuries of persecution, these documents, along with others, were scattered across Roman Empire. There was no New Testament yet; there was no Bible as we know it today.
You remind him that it wasn't until Christian faith was legitimized by Emperor Constantine's decree in fourth century that Church could publicly begin to compile a canon, or rule, of sacred writings. The task required sorting through hundreds of letters and texts attributed to Apostles, evangelists, bishops and saints. The goal was, in essence, to distill truly inspired works from those that were merely inspiring.
Pope St. Damasus I in 382 AD first proposed a list of twenty-seven "books" that would comprise canon. Gatherings, known as synods, of esteemed bishops were then convened in north African cities of Hippo (393 AD) and Carthage (397 AD). These synods prayerfully attempted to discern will of Holy Spirit in deciding what texts belonged in canon and which did not. The Church well understood import of this task. Once canon was decided, it would be closed forever to preclude any tampering.
In year 419 AD a second Council of Carthage was convened under leadership of no less a figure than St. Augustine, a bishop and one of Fathers of Church. This council confirmed canon as approved by earlier synods and forwarded it to Pope Boniface in Rome. The pope then authorized and promulgated text and New Testament became a reality, almost four centuries after Christ.