Put to Death the Flesh to Have a Pure Heart
The powers of darkness come to entice and tempt the brethren to break the law so they can devour us. "Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about seeking someone to devour: whom resist steadfast in the faith (only brethren can have faith), knowing that the same afflictions are accomplished in your brethren that are in the world. But the God of all grace who hath called us unto His eternal glory by Christ Jesus, after you have suffered a while, make you perfect, establish, strengthen, settle you" (1 Pet. 5:8-10).
We suffer as we deny ourselves and resist the fleshly temptations of Satan. We will suffer for a little while, putting to death the fleshly desires, because we love Jesus more than we love the flesh. This was the commandment of the law that we first love the Lord with all our hearts.
The Lord then leads us to die to the selfish flesh in order to have the nature of God and love our neighbor as ourselves: "For ye are all the children of God by faith in Christ Jesus" (Gal. 3:26). The real sons of God put to death the flesh in order to have a pure heart.
The result of this faith is to become doers of the law by loving our neighbor as ourselves. "Do we then make void the law through faith? God forbid: yea, we establish the law" (Rom 3:3 1).
We fulfill the law by being led by the Spirit of God (through faith) to become doers of the law. Jesus Christ came to fulfill the law in us so we could be reconciled to God: "For Christ is the end of the law for righteousness to every one that believeth" (Rom 10:4). If we believe, we will be perfected in love to follow the law.