Quote 4
For a moment, he thought of praying that the horrible sympathy that existed between him and the picture might cease. It had changed in answer to a prayer; perhaps in answer to a prayer it might remain unchanged. And yet, who, that knew anything about life, would surrender the chance of remaining always young, however fantastic that chance might be, or with what fateful consequences it might be fraught? Besides, was it really under his control? Had it indeed been prayer that had produced the substitution? Might there not be some curious scientific reason for it all? If thought could exercise its influence upon a living organism, might not thought exercise an influence upon dead and inorganic things? Nay, without thought or conscious desire, might not things external to ourselves vibrate in unison with our moods and passions, atom calling to atom in secret love or strange affinity? But the reason was of no importance. He would never again tempt by a prayer any terrible power. If the picture was to alter, it was to alter. That was all. Why inquire too closely into it? (8.24)
Again, Dorian backs away from an important turning point; his choice to leave the portrait as it is and not even try to pray forgiveness is a solid check in the "Evil" box.
Quote 5
One hardly knew at times whether one was reading the spiritual ecstasies of some mediaeval saint or the morbid confessions of a modern sinner. It was a poisonous book. The heavy odour of incense seemed to cling about its pages and to trouble the brain. The mere cadence of the sentences, the subtle monotony of their music, so full as it was of complex refrains and movements elaborately repeated, produced in the mind of the lad, as he passed from chapter to chapter, a form of reverie, a malady of dreaming, that made him unconscious of the falling day and creeping shadows.(10.21)
Here, the greatest advocate for evil enters the picture – the poisonous yellow book. It changes Dorian's world immediately, and its seduction blurs the line between good and evil. The book's seduction takes over Dorian's soul.
Quote 6
There was a horrible fascination in them all. He saw them at night, and they troubled his imagination in the day. The Renaissance knew of strange manners of poisoning -- poisoning by a helmet and a lighted torch, by an embroidered glove and a jewelled fan, by a gilded pomander and by an amber chain. Dorian Gray had been poisoned by a book. There were moments when he looked on evil simply as a mode through which he could realize his conception of the beautiful. (11.37)
This is it – here is an admission of Dorian's real acceptance of his innate evil. To him, beauty has gone from being ultimately good (as in Sibyl Vane's case) to being linked to evil. This move of his aesthetic sensibilities represents the completion of the shift in his character.