The conversion of the soul is supposed to be as considerable a work, if not a greater, than the creation, for in the creation God had no adversary. The light did not say, "I will not be created"; the earth did not say, "I will not be formed." But in the new creation, sinners labor to prevent (as much as in them lies) the conception of grace, take down antidotes against salvation, and study how to defeat the Spirit of God and make its works abortive. God, when He comes, finds the house not only empty of grace but filled with lusts and the strong man up in arms; not a milk-white paper, but He finds the devil to have been scribbling and the world to have been scribbling. Angels may knock at the door of a sinner's heart, but God only can open it. The body is not so much at the command of the soul as the soul is at the command of God. "Without me ye can do nothing" (John 15). The Lord opened the heart of Lydia. Man's heart is God's lock, and not man's wisdom; but the Spirit of the Lord is the key that must unlock it. On Jacob\'s Ladder
As the conversion of many people has taken place almost without observation, which often happens in the quieter walks of Christian life, and the conversion of a few only, who at first wandered far off, is incisive like that of an Augustine, such also is the case here. For the most part this witness works gradually and unobserved, and only in exceptional cases is it as lightning that suddenly flames through the skies.Sacred Theology, 560