The Picture of Dorian Gray - Oscar Wilde

…the portrait that Basil Hallward had painted of him would be a guide to him through life, would be to him what holiness is to some, and conscience to others, and the fear of God to us all. There were opiates for remorse, drugs that could lull the moral sense to sleep. But here was a visible symbol of the degradation of sin. Here was an ever-present sign of the ruin men brought upon their souls.