Why is a believer's life different after salvation?
Because the Holy Spirit now controls the believer instead of the world, the flesh, and the devil. The Spirit becomes the guideline for living, producing a changed lifestyle, changed appetites, and a changed thought process. God's love is imparted through the Spirit, enabling the believer to fulfill the law's righteousness.
Les explains that the believer walks not after the flesh or old Adam but after the Spirit. The Spirit becomes the guideline for living, so one of the first marks of true salvation is a change in lifestyle, appetites, and the whole thought process. Whereas the believer was once under the control of the world, the flesh, and the devil, now the Spirit of God controls him. The love of God operating in that believer fulfills the law, for God-given love works no ill to his neighbor, and through the Holy Spirit's power the righteousness of the law is fulfilled in those who walk not after the flesh.