Dorian Gray kills Basil after the artist has viewed the portrait he once painted and sees in it the depravity of soul which has overtaken the once beautiful and untainted young man.
In this Faustian tale, Dorian Gray is a young man whose perfection of features captivates the painter, Basil Hallward. After Basil has finished a portrait of Dorian, his friend Lord Henry Wotton arrives and sees this portrait. Impressed with the painting, Lord Henry tells the artist, "It is your best work...the best thing you've ever done." He urges Basil to send it to the Grosvenor for exhibition; however, Basil states that he will not expose this painting anywhere. He explains,
"I know you will laugh at me...but I really can't exhibit it. I have put too much of myself into it." (Ch.2)
Lord Henry scoffs at this idea, but the artist continues,
"There is a fatality about all physical and intellectual distinction....We shall all suffer from what the gods have given us, suffer terribly." (Ch.2)
Ironically, Basil Hallward's prediction seems to come true. When the young Dorian Gray views his portrait and listens to Lord Henry's speech about the temporal nature of beauty and youth, he looks again at his portrait and ponders how this painting will one day remind him of what he has lost. Influenced by Lord Henry's words, Dorian wishes that he would remain young while the portrait would age. When Lord Henry insists upon owning this portrait, Basil decides to give it to Dorian.
Dorian falls under the influence of Lord Henry and becomes a disciple of the new "Hedonism." He pursues pleasure, and in so doing, he harms some people, notably Sibyl Vane, an actress who kills herself after Dorian rejects her. Following Sibyl's suicide, Dorian notices that his portrait has changed, yet he still looks young and wholesome. Gradually, Dorian engages in more debauchery; nevertheless, his face and body retain the appearance of goodness and youth. The portrait, however, becomes more and more debased and hideous in appearance.
Then, in Chapter 12, Dorian sees Basil Hallward one evening as he walks toward his house. Although Dorian tries to avoid Basil, the painter insists upon accompanying him to his door, saying, "Let me come in for a moment. I have something to say to you." Once inside, Basil tells Dorian that there are terrible rumors about him. Also, he informs Dorian that an old friend of his showed him a letter that his wife wrote to her husband as she was dying alone. Dorian's name was implicated in this letter.
"I wondered do I know you? Before I could answer that, I should have to see your soul." (Ch. 13)
With a mocking laugh, Dorian invites Basil to see his soul because even if he tells others what he will soon view, no one will believe him. Feeling that Basil is the "origin of his shame," Dorian leads the artist to the room where he hides his evil portrait. Tearing the curtain from the painting, Dorian explains that "in a mad moment" he made a wish, "perhaps one would call it a prayer...." (Ch.13) He refers to his youthful wish in Basil's home that the portrait would age and he would not.
Seeing the hideous change in his beautiful portrait of Dorian, Basil Hallward is shocked. He holds a lighted candle to the canvas and observes that the horror and foulness must have come from within, rather than on the surface of the canvas. He thinks it must be some "inner life...the leprosies [sic] of sin were eating the thing away...." His hand shaking, Basil drops the candle and flings himself into a chair, urging Dorian to pray.
"....I worshiped you too much. I am punished for it. You worshiped yourself too much. We are both punished." (Ch.13)
Dorian tells him it is too late for repentance, but Basil insists that it is never too late. "My God! don't you see that accursed thing leering at us?" Dorian tells Basil that he cannot be penitent.
...suddenly an uncontrollable feeling of hatred for Basil Hallward came over him, as though it had been suggested to him by the image on the canvas, whispered into his ear by those grinning lips. (Ch.13)
Dorian is not willing to try to reform; he has become morally corrupt. So, he kills Basil in order to not be exposed to society. Afterwards, he tells himself to "not realize the situation." The man who painted the "fatal portrait" is gone from his life. "That was enough." (Ch.13)