On Being Seekers and Servers of God - A.W.Tozer

Sins of great magnitude may indicate an energy of soul which if turned in a right direction can lead far up the way toward spiritual perfection. Conversely, there is a meanness of soul that inhibits and restricts the scope and intensity of even the most common activities. When such a soul is converted, it may be only to mediocrity.
On his own testimony Paul before his conversion was a great sinner (1 Timothy 1:15). He persecuted Christians with great violence and wrought havoc with the followers of Christ. After his spectacular about-face he turned his magnificent equipment over to the Lord and the whole world knows the result. The same energy of soul that had made him a dangerous enemy of the Christian faith made him a powerful advocate of that faith once his eyes had been opened.

From this we may learn that feebleness and timidity are not to be confused with righteousness. To sin but weakly is not the same as to do good. Lack of moral energy may prevent a man from enjoying himself in sin, but he is in sin nevertheless. His weak effort at neutrality does not deceive God who knows the secrets of every man’s heart.