When we say that the Bible is the Word of God, we mean something very definite indeed. We mean that the Bible is true. We mean that the writers of the Bible, in addition to all their providential qualifications for their task, received an immediate and supernatural guidance and impulsion of the Spirit of God which kept them from the errors that are found in other books, and made the resulting book, the matters of fact, and completely authoritative in its commands. That is the great doctrine of the full plenary inspiration of Holy Scripture.
That doctrine does not, as is so often charged, do violence to the individuality of the Biblical writers; and it does not mean that they became mere automata without knowledge of what they were doing. But it does mean that the work of the Holy Spirit in inspiration was a supernatural work. It was not a mere work of God's providence; it was not a mere employment by God of the resources of the universe that He had made: but it was a gracious interposition into the course of nature by the immediate power of God.
That doctrine means that the Bible is God's book, not man's book. Other books give advice that is good and advice that is bad; this book gives only advice that is good, or rather it issues commands that come with the full authority of the sovereign God.
J. Gresham Machen, The Christian View of Man