Deuteronomy 12:32
See that you do all I command you; do not add to it or take away from it.
Proverbs 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.
Revelation 22:18–19
I testify to everyone who hears the words of the prophecy contained in this book: If anyone adds to them, God will add to him the plagues described in this book. And if anyone takes away from the words of this book of prophecy, God will take away his share in the tree of life and in the holy city that are described in this book.