When the devil is called the god of this world, it is not because he made it, but because we serve him with our worldliness.
Thomas AquinasIt would seem that the ingratitude, whereby a subsequent sin causes the return of sins previously forgiven, is a special sin. For, the giving of thanks belongs to counter passion, which is a necessary condition of justice. But justice is a special virtue. Therefore this ingratitude is a special sin. Thanksgiving is a special virtue. But ingratitude is opposed to thanksgiving. Therefore ingratitude is a special sin.
Thomas AquinasTo restore man, who had been laid low by sin, to the heights of divine glory, the Word of the eternal Father, though containing all things within His immensity, willed to become small. This He did not by putting aside His greatness but by taking to Himself our littleness.
Thomas Aquinas