A common misinterpretation applies this warning to the entire Bible, suggesting no additions or changes can ever be made to Scripture as a whole, whereas the text specifically references 'this book'—the Book of Revelation—indicating a targeted caution against tampering with its unique apocalyptic prophecy; another error views it in isolation without verse 19's parallel prohibition against subtracting, or assumes it limits all future divine revelation rather than preserving Revelation's textual purity for its original audience.
Revelation of John 22:18
King James Version (1769)
18 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:
This verse contains a solemn warning from John, speaking under divine inspiration, to anyone who hears or reads the prophecy of Revelation, prohibiting the addition of any words or teachings to its content, with the consequence that God will inflict upon the offender the plagues described within the book itself, thereby affirming the book's absolute authority, completeness, and sacred integrity as a final prophetic revelation meant to stand unaltered.