Not true. I have faith that electrons travel down a wire. And I turn on my phone and computer and it becomes truth. We have much revealed from God which is not in the bible. Read some science books for instance. We have built vastly upon knowledge revealed by God. Such that now we have MRI machines that can see tumors in the body. But the spirit of wisdom and knowledge are from God. So is the bible the only source of truth and is it a complete description of God and Godly things? Not at all. But I think the scriptures are the work of the Holy Spirit.
1 Corinthians 12:
7But to each one is given the manifestation of the Spirit for the common good.
8For to one is given the word of wisdom through the Spirit,
and to another the word of knowledge according to the same Spirit;
9to another faith by the same Spirit, and to another gifts of healing by the one Spirit,
10and to another the effecting of miracles, and to another prophecy, and to another the distinguishing of spirits, to another
various kinds of tongues, and to another the interpretation of tongues.
11But one and the same Spirit works all these things, distributing to each one individually just as He wills.