I don't follow. How is Peter's authority give us discernment over the trus New Testamant writings? Did Peter put the Bible together?
My Bible is comprised of 66 books-39 Old and 27 New Testament books. All the books contained in them are the correct books. I have no idea what Sola Scripture is.
How do you know? I'm asking honestly.
That's ok if you don't know, I'll try to explain better. Sola Scriptura is basically the belief that everything needed for Salvation is found in the Bible. Catholics believe that the Bible and apolistolic tradition are both needed.
Well Protestants and Catholics now agree that the Bible is infallible, but Protestants do not have the link to Peter, just as they are missing the link to much of the Church's tradition. Catholics believe that the Pope is infallible on matters concerning faith and morals involving the whole Church. In fact, it is strange how the Protestants can determine what books in the Bible are infallible, because they are missing the link to Peter, the rock. Also strange is how they can ridicule Catholics for believing the Pope is infallible when they themselves also believe certain things are free from error.
Protestantism naturally leads to a divergence of opinion on key doctrinal matters (like sola fide-salvation by faith alone which most but not all Protestans agree on, and also Calvin's ideas of predestination). Martin Luther cut seven books from the Old Testament and parts of two others. Is he infallible?
Peter's primacy comes from both the Bible and tradition. In the early Church writers were not sure about many of the books in the New Testament. (Now Catholics and Protestans agree on the New Testament but not the Old Testament.) Even famous and learned writers such as Tertullian were not sure what books were infallible. But what they were sure on was that the Pope's decision was final, through apostolic tradition.
So Peter did not pot the Bible together, but his sucessors (the Popes) did. Even the Protestants agree on the Popes decisions regarding the New Testament books. Martin Luther said so himself. I hope this answers your questions.