John wrote that we are to keep the commandments:
And hereby we do know that we know him, if we keep his commandments.
1 John 2:3,4
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.
By this we know that we love the children of God, when we love God, and keep his commandments.
1 John 5:2-4
For this is the love of God, that we keep his commandments: and his commandments are not grievous.
For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith.
Paul also wrote about the importance of faith and keeping the commandments. Peter cautioned however that some would twist Paul’s words around and take them out of context, claiming for example the ten commandments were no longer valid:
As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.
2 Peter 3:16