New Testament Inspired?

Someone asked me a good question the other day. She asked "How do we know that there the 27 books we have are inspired by God and that there aren't any other books that should be apart of it? And who determines which New Testament books are and aren't inspired? Didn't Paul write more than 13 letters? Why are only 13 recorded?"

I can't say I have the answer to this. I obviously know the Old Testament Scriptures are inspired because Jesus quoted them all. However, with the New Testament, what can we say from Scripture to show the lost that the 27 books we have are inspired?

Any thoughts...

I don't really know how to explain this to anyone, but I have reconciled it long ago to my own soul that the Bible is what it is soley by the design of God. God sovereignly decided which books to include, and which books to exclude...even regarding those written by Paul. God chose to exclude Paul's letters to Dalmatia and Laodicea for a reason. The Holy Bible we have today is perfect and complete in its entirety by the express will of God. This is what I believe, this what I accept, and the 66 books God has given me is enough for a million lifetimes of meditation.

When you begin to look at all 66 books of the Holy Bible as God's own specific, personal design by which He wrote, compiled and edited (using men as His instruments) to fulfill this very purpose, all these perplexing questions clear up instantly. Now, explaining this to a skeptic is futile. God must reveal it, as God revealed it to you. Until these scales fall away, people will debate Bible inerrancy and regard its compilation as arbitrary.