Revelation 22:18
I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book.
World English Bible (Public Domain)
In context
Before · Revelation 22:16–17
16I, Jesus, have sent my angel to testify these things to you for the assemblies. I am the root and the offspring of David, the Bright and Morning Star.” 17The Spirit and the bride say, “Come!” He who hears, let him say, “Come!” He who is thirsty, let him come. He who desires, let him take the water of life freely.
18I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book.