Here is a fascinating statement from one scripture about the varied nature of the rest of scriptural, and non scriptural revelation.
Hebrews 1:1-4 ESV
Long ago, at many times and in many ways, God spoke to our fathers by the prophets,  but in these last days he has spoken to us by his Son, whom he appointed the heir of all things, through whom also he created the world.  He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high,  having become as much superior to angels as the name he has inherited is more excellent than theirs.
One can read the Bible as if it were flat, like a map. There are markings but only in two dimensions. Or one can read it and notice the variation, and see it more like one of those world globes with raised mountains and groves for rivers. The anonymous author of the book of Hebrews starts with this presumption. He asserts that in contrast to the many and varied means of revelation, the final word is found in Christ.
What are these ways and means? Luke spoke of careful research (Luke 1:1-4), Exodus speaks of God speaking and writing messages to Moses (Exodus 18-20), Prophets sometimes had visions (Isaiah 6), other times it says “the word of the Lord came to X…”, Psalm 19 speaks of the witness of Nature and of the scriptures, there was a provision for the High Priest to use divining tools (urim and thummim- Ex 28:30) to find God’s word, the scribes gathered Proverbs from many sources, some were freshly written (Solomon was said to have written many- I Kings 4:29ff). So we see a variety of modes of revelation – from homework to visions.
There are a variety of literary styles and genre. Clearly poetry differs from narration, law differs from wisdom, parables from discourses and so forth. There are three languages: Hebrew, Aramaic and Greek. There are many literary devices.
For this reason the Proverbs begin with a goal that the reader become skilled in understanding the sayings of the wise.(Pv 1:6) It is not as easy as falling off a log.
We do not believe that the scriptures are unaccessable, but that the more one knows about the texture of scripture the better one understands it.