The reason believers can have victory through Christ is that the power of the indwelling Spirit of Christ is greater than the power of the old sinful nature.
The downward pull of the sinful nature may be likened to the downward pull of the earth’s gravity. A stone thrown into the air will fall to the ground, because it has no life or power to overcome the force of gravity. We have a living power that enables us to overcome the downward pull of the flesh. We have a new ‘law’, LIFE, which is greater than the ‘law’ of gravity.
Likewise in Christ believers have a new upward force of the Spirit that is greater than the downward pull of the flesh.
Efforts to keep the law cannot produce righteousness, because flesh cannot be cured, or even improved. It can only be condemned to destruction, and Christ did this by his death on the cross. When, however, believers live according to the power of the Spirit, we can develop in our lives the righteousness that the law aimed at but could not produce.
The mind cannot be controlled at the same time by both the flesh and the Spirit. One results in hostility to God, the other in peace. One leads to death, the other to life.
The Spirit within believers is the Spirit of Christ. Through the Spirit, Christ dwells within us, giving us spiritual life, victory over the flesh, and in the end freedom from even the last physical effects of sin, death.
Since the flesh is no longer our master, Christians should not obey it. Rather we should kill off its sinful actions. We are now children of God, free from the fear of bondage and led by the Spirit. Our union with Christ means that one day we will share in the Father’s inheritance, but it also means that in the present life we must share in Christ’s suffering.
Romans 8:1–18