You are correct. Rev 22:18-19 are specifically talking about the Revelation given to John. We have to search the rest of scripture to find out the answer to additional revelation from God and how to tell if it is of Him.

There are other similar warning given in the Bible:

Duet 4:2 “Do not add to what I command you and do not subtract from it, but keep the commands of the LORD your God that I give you.”

Duet 12:32 “See that you do all that I command you. Do not add to it or take away from it.”

Prov 30:5-6 “Every word of God is flawless; he is a shield to those who take refuge in Him. Do not add to His words, or he will rebuke you and prove you a liar.”

It is a principle found in scripture that we are not to change the word of God in any way whatsoever. Severe warnings are given to those who consider it. Yes the warning you mentioned is specific to the book of Revelation, but it’s principle is timeless.

So we must test all that man reveals, especially when he says it is revelation of the Lord, with what God has already revealed to us. God is unchanging from beginning to end (Malachi 3:6, Hebrews 13:8, Psalm 102:25-27). The bible warns us to test the prophets in two specific ways.

First, if they say God has given them insight to future events, then those events must take place 100% as predicted by that prophet (Duet 18:20-22). This is for our protection, so we know which prophet is of God. This makes sense, because only God knows the future (Isaiah 42:9). Therefore he could not tell us something that does not come to pass exactly as predicted, because God is outside of time and has already seen it take place. If you want a perfect example of the type of fulfillment necessary, take a look in two places. First, the prophet Daniel. He successfully predicted the succession of nations exactly as they were to take place, in great detail. His predictions were hardly coincidental, or vague. And take a look at Christ himself. In Matthew 24, Mark 13, and Luke 21 Jesus predicted in detail the destruction of the temple that would take place 40 years in the future. He stated that all those things would take place withing that generation, and they did 100% as predicted. That is the standard of a prophet.

The second is to test what the prophet has said in light of what has already been revealed. Dueteronomy chapter 13 states this principle. Because God is unchanging he will not contradict revelation he has given, or change it. This is also for our protection.

So any person that claims to be a prophet speaking for the Lord must pass these two tests. There future predictions must come to pass as told, and they must not contradict revelation already given. 

So each and every one of us must check out these men, and in the point of the LDS faith, the prophets of today and yesterday. And you will find clearly that they have changed what each other has said, revealed new contradictory information, and outright failed to predict the future. This is objective, factual information for our protection.

Please, check these things out for yourself, and be convinced in your own mind what the scriptures say and test that in light of what these prophets of today say, regardless of religious affiliation. Not the least of which would be Joseph Smith. your comments are graciously welcome. 

As far as your comment about nothing shall be taken away or added to it, referring to the Bible, please make sure you have the appropriate facts about how the Bible was put together, as you have contradicted yourself since I’m sure you have accepted EVERYTHING in the Bible.

The Bible is NOT in chronological order.  The Book of Revelations was not the last book written.  In fact, all of the Gospels were separate before they were put together as one, making up the Bible as a whole.  When that was written in the Book of Revelations, it was not referring to the whole Bible, as there was no Bible at that time, it was referring ONLY to the Book of Revelations.  And since it is not in chronological order, does that mean you don’t accept the other “books” in the Bible that occurred after the Book of Revelations was written?  I am sure not. Therefore, your argument isn’t a valid one since you yourself has accepted the Bible as a whole, which completely contradicts everything you said about not adding or taking away.

Heavenly Father loves ALL of his children, including those of us who are on the earth NOW.  It only makes sense that he would give us a prophet today and additional scriptures that we can learn from as those who wrote the writings in the Bible are not the only ones who have ever had dealings with God.  We need these things now more than ever to prepare the earth for one of the most major events it will ever see, The Second Coming of his Son.  He has ALWAYS had prophets to testify of Christ before he comes and now is no exception.  As I stated earlier, he loves us just as much as he loved them in the past.

I appreciate your comments.    In regards to the timing of the death of those spoken of in 1 Peter 4:6, I will trust that there is no verb “are” in the verse, and that the phrase might best be translated without one.  So if you’re right, it seems consistent with both interpretations: that they were alive at the time, but are currently dead (as you interpret), but also that they were dead at both times.  I’ll point out that the syntax is ambiguous in any language.  Even so, if I say to you, “I spilled lemonade on the dead guy,” which of the two do you think of first?

Regarding the aorist tense, indicative mood: although wikipedia reports that “the aorist usually implies a past event in the indicative, but it does not assert pastness, and can be used of present or future events,” I’ll trust you know more about it than I do, and I’ll grant that it is speaking of an event that actually happened in the past.  

Regardless, I can’t find anywhere on this post or elsewhere where Mormons are claiming that the text of 1 Peter 4:6 is in the present tense.  As far as I can tell you’re arguing against a point that no one is making.