Virtues and vices are the food of the soul and it can feed on either one, turning to whichever one it wants. If it is bent toward moral excellence, it will be fed by virtue - by righteousness, temperance, meekness, endurance. In other words, it is just as St. Paul says, 'being nourished by the word of truth' (1 Tim. 4:6).
St. Ignatius of Antioch