What I command to you, this only shall you do, for the Lord. You may neither add nor subtract anything.
Other versions
King James Version
What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.English Standard Version
"Everything that I command you, you shall be careful to do. You shall not add to it or take from it.New International Version
See that you do all I command you; do not add to it or take away from it.