“For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book: And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book. He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus. The grace of our Lord Jesus Christ be with you all. Amen” (Revelation 22:18-21).
Because the book of Revelation is the last book in the Bible, and because many have come to think of it as one single book, instead of being a library of 66 books, not a few have taken this final malediction to be referring to anyone who messes around with the contents of Scripture. No doubt that is *also* a bad thing to do, but the curse that is stated here is a curse that applies to the contents of the book of Revelation itself. The reference is to this book, and a particular feature of the Apocalypse all the plagues of the book are specifically mentioned and applied.
Now what is true of the parts also happens to be true of the whole. If someone ought not tamper with the book of Revelation, it would not be good to tamper with the books that came before. This is a scriptural way of thinking.
Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the Lord your God which I command you (Deut. 4:2).
What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it (Deut. 12:32).
Add thou not unto his words, Lest he reprove thee, and thou be found a liar (Prov. 30:6).
The malediction is for those who adjust the content of the Scriptures to suit themselves. It should not be applied to those who disagree with us about the precise meaning of the seventh bowl of wrath.
If a person supplements this revelation with his own thoughts, then God will supplement him with all the plagues mentioned. If someone takes away from this revelation on the basis of his own wisdom, then God will take away his portion of the Book of Life, and his portion in the holy city, and from the things (e.g. blessings) that are mentioned in this book. This does not mean that someone can be removed from Gods roster of the elect. But it does mean removal from the covenanted and visible church, and all the blessings that pertain to it.
The one who testifies to these things that is, the Lord Jesus says that He is coming quickly. John responds with a heartfelt invitation even so, come, Lord Jesus. And the book concludes with a simple but glorious benediction. The grace of our Lord Jesus Christ be with you all. Amen.