The only book with a warning label at the end is Revelation
The book of Revelation is the only book of the Bible that comes with a warning to those who would add to the words of this book of prophecy (the book of Revelation) and to those would take away from the words of the book of this prophecy (the book of Revelation). This warning can be found in Revelation 22:18-19 (GFS)
18 For I testify to everyone who hears the words of the prophecy of this book: If anyone adds to these things, God will add to him the plagues that are written in this book; 19 and if anyone takes away from the words of the book of this prophecy, God shall take away his part from the Book of Life, from the holy city, and from the things which are written in this book. –Revelation 22:18-19 (GFS)
To what degree you have to add or take away from the book of Revelation to find yourself in trouble is unknown. I hope you have to really be trying to go against God in order to be guilty of this violation, because just about everyone, with their uninformed comments, makes remarks about the book of Revelation or the events contained in it. Does that constitute adding or taking away? I don’t know. What I do know is that I have studied the book of Revelation for years and the things I know I will talk about. The things I don’t know about it I will quickly say that I don’t know. I won’t make any assumptions unless, to the average rational person, the assumption is obvious.
Before you decide to put in your two-cents worth about the events found in the book of Revelation you should probably ask yourself a few questions. Here are some examples. “How informed am I about the information found in the book of Revelation?” “How much can I discuss about the book of Revelation without having to open my Bible and look up scriptures?” “Have you been called by God to teach about the book of Revelation?” I would imagine that if you don’t have a thorough working knowledge of the book of Revelation, this might be one book you shouldn’t be talking about. And that of course includes all the topics that are discussed in this book. Why run the risk? Remember, this is the only book of the Bible with a warning about adding or taking away from it. And the penalty, well, it’s pretty clear that the penalty is the loss of your salvation.