It is frequently difficult to wrap one's mind around the body of scripture. Over the years the content of the canon has come under great debate and scrutiny. A "canon" is a measuring rod or standard by which content is measured. It is carefully thought through and it adheres to the concept that all truth is consistent with itself.
Our canon of scripture contains 66 books written over approximately 1600 years by about 36 authors. These writings are made up of genealogies, laws, historical summaries and stories, poetry, prophecy, and doctrinal and practical letters to churches, pastors or individuals. This collection can be thought of as one book (or library) with one subject: God's relation to and redemption for humankind.
There are many writers but just one author -- the Holy Spirit. 2 Timothy 3:16 says: "Every scripture is inspired by God and useful for teaching, for reproof, for correction, and for training in righteousness." And 2 Peter 1:20-21 says: "No prophecy of scripture ever comes about by the prophet's own imagination, for no prophecy was ever borne of human impulse rather, men carried along by the Holy Spirit spoke from God."
Hebrew was the language for recording the older documents with some parts (whole chapters or certain verses) in Aramaic. The newer documents of Jesus' time and following were written in common (koinay) Greek, a Greek structure different from classical Greek but validated by the relatively recent (late 1700s - early 1900s) discovery of thousands of papyrus documents. Many were stuffed into crocodile mummies in a sacred crocodile cemetery.
In the course of document collection, the sacred scripture possesses significantly more ancient copies than any other literature and has been found to be significantly more accurately copied than any other literature. Any copy differences that have been found do not in any way impact the doctrinal content. Through this we see that God does superintend the creation and preservation of his covenant with humankind.
Attempts to Discredit Scripture
Over the last couple centuries, there have been many who have tried to discredit the sacred scriptures. They devise a hypothesis and try to impose that on scripture, and search for some artificial hook that they can use to support their view. The reason for this is due to their lack of acceptance that God is the God of scripture and that his speaking is truth. Truth hurts when it contradicts your desired belief. If a document can be made to look like a common (non-sacred) document by discrediting a prophecy and its fulfillment, then the hypothesis would be to find some way to make it look like the document was "historically" written after the "prophecy fulfillment."
These textual criticism and higher criticism hypotheses are so full of flaws that it is not worth time spending looking at them. It comes back to the same issue presuming their major premise is to be trusted more than God. Other flaws of interpretation come through the improper use of grammar. Several cults have built their fundamental doctrines based on the grammatical structure of the original language being interpreted by the grammatical structure of the translated language. You cannot force syntactical structures from one language upon another and expect to come up with the correct meaning. This is a immature and incompetent process, and is intended to seduce hearers into believing their heresy.
Chapters and verses do not come with the original document. Chapters were created around 1225, and verses were added around 1550. These are handy ways to get at specific passages (we use them all the time), but they can often interfere with proper understanding of the context because we use the artificial breaks as limits on the context. Even though chapters and verses will be used in these articles, don't let those limit understanding the context.