This post was first published in July, 2016. —ed.
Over the last hundred years, the church has seen an explosion of interest in the Holy Spirit—particularly in His work of empowering God’s people and revealing His truth. This renewed interest in the Spirit’s role in our daily lives has injected excitement and enthusiasm into many churches, as the Lord seems to be revealing Himself and His power in wonderful ways.
But for believers caught up in tales of a fresh unleashing of the Spirit, it may be hard to see the difference between what God is saying and doing today and what He said and did in the days when Scripture was being written. We must ask the question: Is there a difference between God’s Word as given then and the word He is supposedly speaking to and through believers today?
I think there is a major difference, and it’s something we must keep in mind if we are to keep the authority and infallibility of the Bible in proper perspective.
The Canon Is Closed
The truth is there is no fresher or more intimate revelation than Scripture. God doesn’t need to give us private revelation to help us in our walk with Him. “All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; so that the man of God may be adequate, equipped for every good work” (2 Timothy 3:16-17, emphasis added). Scripture is sufficient. It offers all we need for every good work.
Christians—particularly charismatics, as well as those who are merely “open but cautious”—must realize a vital truth: God’s revelation is complete for good. The canon of Scripture is closed. As the apostle John penned the final words of the last book of the New Testament, he recorded this warning:
I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book; and if anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life and from the holy city, which are written in this book. (Revelation 22:18-19)
When the Old Testament canon closed after the time of Ezra and Nehemiah, there followed four hundred silent years when no prophet spoke God’s revelation in any form.
That silence was broken by John the Baptist as God spoke once more prior to the New Testament age. God then moved various men to record the books of the New Testament, and the last of these was Revelation. By the second century A.D., the complete canon—exactly as we have it today—was popularly recognized. Church councils in the fourth century verified and made official what the church has universally affirmed, that the sixty-six books in our Bibles are the only true Scripture inspired by God. The canon is complete.
Just as the close of the Old Testament canon was followed by silence, so the close of the New Testament has been followed by the utter absence of new revelation in any form. Since the book of Revelation was completed, no new written or verbal prophecy has ever been universally recognized by Christians as divine truth from God.
Dividing Truth and Error
Jude 3 is a crucial passage on the completeness of our Bibles. This statement, penned by Jude before the New Testament was complete, nevertheless looked forward to the completion of the entire canon:
Beloved, while I was making every effort to write you about our common salvation, I felt the necessity to write to you appealing that you contend earnestly for the faith which was once for all handed down to the saints. (Jude 3)
In the Greek text, the definite article preceding “faith” points to the one and only faith: “the faith.” There is no other. Such passages as Galatians 1:23 and 1 Timothy 4:1 indicate this objective use of the expression “the faith” was common in apostolic times. Greek scholar Henry Alford wrote that the faith is “objective here: the sum of that which Christians believe.” 
Note also the crucial phrase “once for all” in Jude 3. The Greek word here is hapax, which refers to something done for all time, with lasting results, never needing repetition. Nothing needs to be added to the faith that has been delivered “once for all.”
George Lawlor, who has written an excellent work on Jude, made the following comment:
The Christian faith is unchangeable, which is not to say that men and women of every generation do not need to find it, experience it, and live it; but it does mean that every new doctrine that arises, even though the legitimacy may be plausibly asserted, is a false doctrine. All claims to convey some additional revelation to that which has been given by God in this body of truth are false claims and must be rejected. 
Also important in Jude 3 is the word translated in our English Bibles as “handed down” or “delivered.” In the Greek it is an aorist passive participle, which in this context indicates an act completed in the past with no continuing element. In this instance the passive voice means the faith was not discovered by men, but given to men by God. How did He do that? Through His Word—the Bible.
And so through the Scriptures God has given us a body of teaching that is final and complete. Our Christian faith rests on historical, objective revelation. That rules out all inspired prophecies, seers, and other forms of new revelation until God speaks again at the return of Christ (cf. Acts 2:16-21; Revelation 11:1-13).
In the meantime, Scripture warns us to be wary of false prophets. Jesus said that in our age “false Christs and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect” (Matthew 24:24). Even extraordinary signs and wonders are no proof that a person speaks for God. John wrote, “Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world” (1 John 4:1).
Ultimately, Scripture is the test for everything; it is the Christians’ standard. In fact, the word canon means, “a rule, standard, or measuring rod.” The canon of Scripture is the measuring rod of the Christian faith, and it is complete.
Used with permission from John MacArthur.