One clear example of Fagin's greed can be seen in Chapter IX of Charles Dickens's Oliver Twist. In this chapter, after Fagin believes Oliver has fallen asleep, he pulls out a box hidden in the floorboards. As he raises the box's lid, "his eyes glisten." From the box, he pulls out various treasures, including multiple bejeweled gold watches, "rings, brooches, bracelets, and other articles of jewelry." With each piece he pulls out, Fagin "distort[s] every feature [of his face] with a hideous grin" and "survey[s] [each piece] with equal pleasure." He also mutters to himself comments that are not entirely understandable but must have to do with how he managed to acquire each piece of jewelry. From this description, we know he is secretly, obsessively admiring a multitude of very costly pieces of jewelry. The irony in this scene concerns the fact that Fagin lives in extremely rundown dwellings and that both Artful Dodger and Charley Bates believe Fagin to be taking care of them; however, it seems in actuality Fagin is hoarding enough wealth that they could be living in comfort. Fagin explains he is hoarding it to live on in his old age and calls himself "a miser." Hence, as we can see, even Fagin believes this scene perfectly depicts his own greed.
A second example of Fagin's greed can be seen in the fact that Fagin works tirelessly at convincing Oliver to join the gang of thieves. He uses such persuasive tactics such as keeping him locked up, never leaving Oliver alone, constantly having Dodger and Charley Bates play the game of practicing to pick pockets with him, talking about how profitable the trade of thievery is, and "tell[ing] stories of robberies he had committed in his younger days" (XVIII). The stories were so funny that Oliver couldn't help but laugh, which eventually made him feel positively about the trade despite his moral reservations. All of Fagin's actions served to eventually "poison" Oliver's soul and persuade him to become a thief, as we see in the narrator's following explanation:
In short, the wily old Jew [Fagin] had the boy in his toils. Having prepared his mind, by solitude and gloom, to prefer any society to the companionship of his own sad thoughts in such a dreary place, he was now slowly instilling into his soul the poison which he hoped would blacken it, and change its hue for ever. (XVIII)
Fagin's desire to "blacken" Oliver's soul indicates he is not content to let people think and feel as they wish to feel, showing us that he is selfish and manipulative. What's more, since Fagin wants to convince Oliver to thieve for him for his own profit, we can see that Fagin's desires to turn Oliver into a thief are a perfect illustration of Fagin's greed.