Deuteronomy 4:2 King James Version (KJV)
2 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.
Revelation 22:18-20 King James Version (KJV)
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:
19 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.
20 He which testifieth these things saith, Surely I come quickly. Amen. Even so, come, Lord Jesus.