A book will reflect something of the book’s author. The author of the book is the one from whose mind the book and its contents originate. The writing of Shakespeare differs from that of J.K. Rowling, for example.
Strictly speaking, the Bible has one Author—the Holy Spirit, or God Himself. God determined the whole Bible and its contents. However, God did not, as He did with the Ten Commandments, write the Bible directly with His finger. Instead, He prepared men as human instruments—human writers—to write the Bible, which is His Word. Since the Bible is the Word of God, and not the word of man, it has certain characteristics.
First, it is inerrant, which means that it contains no errors, and infallible, which means that it cannot err. The Word of God is the Word of Him who cannot lie. No man can write an infallible book—especially an infallible book consisting of 66 infallible books. Jesus declared concerning the Bible, “The Scripture cannot be broken” (John 10:35). David wrote, “The words of the Lord are pure words: a silver tried in a furnace of earth, purified seven times” (Psalm 12:6).
Second, it is authoritative. The words of Charles Dickens or Roald Dahl have no authority. Since the Bible is the Word of Him that sits upon the throne of heaven, it has ultimate authority—for what we believe, and for how we behave. It is according to this Word—and no other—that God will judge all men. There is no higher authority—not the opinions, or feelings or customs of men; not the writings of theologians or scientists; and not the decrees or dogmas of the church. “God has spoken” is the end of all debate.
Third, it is sufficient for doctrine (or teaching) and life. Everything that we need to know about God is revealed in Scripture. Nothing can be added to Scripture, and nothing can be taken from Scripture. God no longer gives new revelation by His Holy Spirit—everything has been recorded in the 66 books of the Bible, from Genesis to Revelation.
Fourth, and finally, God’s Word is clear. The Bible is not an incredibly complicated book. It is not a book only for scholars. All believers can and must read, study, understand, believe and obey it. There are parts, of course, which are more difficult than other parts, but what Jesus says is true, “Search the Scriptures, for in them ye think ye have eternal life: and they are they which testify of me” (John 5:39).