The following is taken from RC Sproul’s article “The Establishment of Scripture,” from the 2009 edition of Ligonier Ministries’ Sola Scriptura: The Protestant Position on the Bible.
The claims of private revelations are many. Pat Robertson has routinely received a “word of knowledge” on national television. He says God reveals specific illnesses of people who live in various parts of the nation as he prays. I have seen him say things like, “Someone in Topeka, Kansas, is being healed of a goiter right this moment.” This is an astonishing thing. Here is a man hundreds of miles from the scene who is getting supernatural revelation of the healing of a specific disease in a specific city. But what puzzles me is the restricted specificity of these revelations. The disease and the city are named, but never the name and address of the person being healed. Consequently, the prophecy can be neither verified nor disproved.
Oral Roberts once told the nation that God had revealed to him that his life would be taken if he didn’t raise a large amount of money in donations. Robert Tilton promised his constituents that he would mail them a special message from God if they sent in their donations. These, of course, are crude forms of modern claims to added revelation. How these claims can be entertained by the credulous is a matter of consternation for me.
But it gets more subtle. We hear respected Christian leaders claiming that God has “spoken to them” and given specific guidance and instructions they are duty-bound to obey. They are careful to note that this divine speech was not in audible form and there is a disclaimer that this is not new “revelation.” Yet the message that is “laid on the heart” is so clear and powerful that to disobey it is to disobey the voice of God. I am not speaking here of the work of the Holy Spirit, by which He illumines the text of Scripture in such a sharp manner as to bring us under conviction or direct our paths; in such times, the Spirit works in the Word and through the Word. I am speaking of the voice of the Spirit that men claim is working apart from the Word and in addition to the Word.
Though such claims are more often than not attended by the disclaimer that they are not revelation, the way they function is as revelation, so that the distinction between them and bona fide revelation is, in actuality, a distinction without a difference. [pg. 56]