In several ways the Mormon notion of continuing revelation makes sense. If God is a personal God who cares about us, wouldn’t he want to continue to direct us? Likewise, if God is at least relatively infinite and us comparatively finite, then it also follows that we have a lot more to learn and God has a lot more to reveal to us about truth. On many levels this idea has appeal, especially as it is so ordered in the Mormon hierarchy as to exclude the possibility of confusion. The usual evangelical Christian responses to Mormon continuing revelation and the ‘extra’ scripture that follows is to quote out of context biblical verses that don’t really work for their argument (for instance the verse from Revelation really only applies to the book of Revelation). Is there a firm basis by which the orthodox Christian world might disagree?
All of those ‘extra’ scriptures Mormons have are ‘extras’ because they tend to have the effect of distraction. The orthodox Christian story is a rather simple one overall: God creates creatures with the freedom to truly love him back, these finite creatures cannot be united to their infinite God alone, God erupts his finite creation by becoming a creature himself. Via the book of Hebrews the Old Testament can be seen as primarily a collection of foreshadowing providing many different ways to understand The Event- the incarnation of the infinite God as Christ. The New Testament restricts itself to discussing the meaning and ramifications of this event to those who had access at least to those who did have first hand interaction with Christ and so it ends. There is no continuing revelation because The Revelation has happened, at a moment in history, two thousand years ago. While we can always discuss and interpret and apply The Revelation, The Event, there is no more universal revelation to be had lest it distract from the greatest happening that will ever happen to us until history ends.