How can anyone be certain then of the Bible's validity, if not all of ''God's word'' was included?
This is the same problem Muhammad faced, there were numerous sects of Christianity to begin with, with many unorthodox views.... If you compare the many accounts within the additional texts, overall they create a completely different Yeshua.
So as in my debates running on
here, it is better to first establish who is Yeshua, with gospels that confirm each other. So in Matthew, Mark and Luke we see an overall matching character, with a clear representation of prophetic understanding in parables.
What is more concerning is not what they kept out, as a lot of the gnostic gospels are very whimsical; yet that they kept in the letters of Paul, the gospel of John and the writings of Simon.... The reason they did this, is they want direct apostolic succession, so they can claim the church is ordained; even if it provides numerous contradictions in theology, which they've then made forcibly fit (hypocrisy).