Deuteronomy 12:32 in the King James Version
What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.
Context
31 You shall not do so to the LORD your God; for every abomination to the LORD, which he hates, they have done to their gods; for they even burn their sons and their daughters in the fire to their gods.
32 Whatever thing I command you, that you shall observe to do. You shall not add to it, nor take away from it.