| Romans 7: 21,
"I find then a law, that, when I would do good, evil is present with
What Paul knows and reveals is that man does not always live up to what he intends. He may have good intentions, but can sin to his own destruction nonetheless. One may even delight in God's law, but unless he keeps that law he is guilty of sin. The inward man, the spirit of man, may well see the good of God's way. But there is a conflict being fought, and an on-going spiritual war. His war is between the mind and the body; between the spiritual requirements of the law that appeals to the mind of man, and the temptations of sin that appeal to the fleshly appetites of the body.
The man of God, so long as he lives on this earth, shall be engaged in such a conflict. He must learn to overcome evil with good rather than be overcome with evil.