The entire Bible is a product of the Holy Spirit, who is not only “the Spirit of truth” (John 16:13), but “the spirit of prophecy” (Revelation 19:10). The verb “to prophesy” (derived from Greek preposition pro and verb phemi) means “to speak forth before.” The preposition “before” in this use may mean 1) “in advance” and/or 2) “in front of.” Thus, “to prophesy” is a proper term to describe the proclamation of God’s Word as it forecasts events. It may also describe the declaration of God’s Word forthrightly, boldly, or confrontingly before a group or individual—telling forth God’s truth and will. So, in both respects, the Bible is prophetic: a Book that reveals God’s will through His Word and His works, as well as a Book that reveals God’s plans and predictions.
This text defines the witness or testimony of Jesus Himself as being synonymous with, or at the heart of, the spirit of prophecy. These words not only define Scripture; they also confine all utterances that claim to be true prophecy: Jesus Christ will be at the center of it all, as He is in the whole Bible. 1) The Old Testament exists to reveal Christ (Luke 24:27; John 5:39; 1 Peter 1:10–12); and 2) the New Testament is inspired by the Holy Spirit for the same purpose (John 14:26; 16:13–15).