This is a question a sincere Christian may agonize over after learning that some books of the Bible were rejected by certain early Christian groups,while other books that did not make the canon were accepted. Also,when one realizes that so called inspired writers of the Greek scriptures quote from apocrypha,that most Christians reject today,one wonders if these writings that include these quotes should even be in the Bible.
It is true that when it comes to the Christian Greek scriptures the canon has been closed for many centuries. Also, these books have been accepted by Christians ever since the second,perhaps first,century. But wait! Around 170c.e. 2 Peter was doubted as inspired in certain quarters, around 180 Hebrews was doubted, 190-Hebrews,1&2 John and Jude. 230c.e. -Hebrews,James, 2 Peter, 2&3 John and Jude. Also, according to the Muratorian Fragment of 170c.e., the church accepted an apocalypse of Peter,which never made it in the canon of today.
Yes, we as Christians can believe that God gradually directed certain writings to be weeded out,while others included. My objection is- why was there such confusion of which ones were inspired around the time of their writings? Why did God not make it explicitly clear which ones he "breathed on"? No where in the Bible does it say God would direct the formation of books for the Christians.
Now,for me, I feel that every Christian book is in harmony with God's will and standards,whether inspired or not. Thetefore I believe at the very least that he approves of these writings for us to live by; even if some may have written things that are not accurate. When it comes to inspired topics, the writer usually says he had a vision or revelation prior to his writing about it. Therefore at best,the vision was inspired,not the writing of it. This whole topic does concern me because when I read my Bible I want to be sure that at least it has God's approval;and that Iam not just studying a man's oppinion about God.