I already explained this. Not everyone believed that 2 Peter WAS Scripture, nor even WRITTEN by Peter. So how can we base "what is Scripture" on a letter that Christians weren't sure on, that many disagreed on its inerrancy? The Church didn't take 400 years to decide that Paul's letters were Scripture. Some of them were noted as Scripture by future writers in the second century. But some of "Paul's" writings were debatable. Hebrews. The Pastorals. Did Paul write them? Evidence is clear that not everyone was sure about their authenticity. There appears to be a gradual acceptance of the Pauline Corpus, but none of this was ever universal until the Church declared it so.
And last I looked, the NT consists of more than some writings from Paul and the Gospels... Where does the Bible state that James is inspired by God? John's Epistles? Jude? 2 Peter? The fact of the matter is that regarding doctrine, the Church DEFINES issues when there is disagreement on true teachings. The reason for councils was to define and weigh in on one side or the other. The same is true on the Canon of Scripture.
Regards
The very fact that it is NOW included in the Canon should attest to it's infalliblity. Wouldn't that be correct?
Where does the Bible state that James is inspired by God? John's Epistles? Jude? 2 Peter?
In fact there were very few books that were called into question. Peter considered Paul's writings inspired. Undoubtedly the early church felt the same about Peter's writings. These writings were guarded. They were not oral traditions and they did not disappear. Nor did the church fathers sit around scratching their heads trying to decide what books to quote from. There is no better evidence than Peter's own words which the Church has deemed "inspired".
Some would like us to believe that the Church's council got together in the 4th century and magically strung all these books together, picking and choosing. You say that Peter had the keys to the kingdom and it was handed down in succession providing a clear documented trail back to Peter. And then you tell us nobody knew what books were inspired until the 4th century. Doesn't this seem a bit odd?
In truth all but a few of the writings were already validated and verified all the way back to Peter. (To deny this is to deny the inspiration of Peter.) And people were reading them. There are a handful of books that raised questions but these were only a few; not the many as we are led to believe. The purpose of closing the scriptures according to Augustine was to keep the Gnostic writings out; not for the Church to stamp their seal on God's word.