As early as Chapter 2, the novel foreshadows that a prominent character will die by hanging:
"That boy will be hung," said the gentleman in the white waistcoat; "I know that boy will be hung."
Nobody controverted the prophetic gentleman’s opinion.
Oliver has been a squeaky wheel at the workhouse, asking for more food and asking not to be apprenticed to a cruel man. The man in the white waistcoat sees his failure to comply at all turns as evidence that Oliver will turn into a criminal who will eventually be caught and executed. It seems from this instant that Oliver himself might be hurtling his way toward hanging.
Because of his terrible circumstances, Oliver indeed must sort out whether a life of crime or a life free of crime will result in the greatest chances of survival. Especially once he falls under Fagin's thumb, it seems likely that he will have no choice but to survive through crime until he is caught and hung. Charley Bates reinforces hanging as the fate that awaits criminals, teasing Oliver about this inevitable end in Chapter 18:
Master Bates caught up an end of his neckerchief, and, holding it erect in the air, dropped his head on his shoulder, and jerked a curious sound through his teeth, thereby indicating, by a lively pantomimic representation that scragging and hanging were one and the same thing.
Criminals, such as the ones Oliver and Charley are shaping up to be due to their circumstances, are so sure to meet their end in capital punishment that Charley seems to think they may as well make light of it.
Both the man in the white waistcoat and Charley turn out to be correct that criminality is a long walk to the scaffold. But there is a twist to the end that has been foreshadowed throughout the novel. It is not Oliver who hangs, but rather Sikes, a man who actually commits murder. Oliver's narrow escape from criminality seems to set him on the path for a happy ending. Notably, the man in the white waistcoat also dies before the end of the novel. Although Dickens presents a fairly inflexible view of the fate of those who do go down the path of crime, he raises the question of who ought to be considered a criminal. Some people, such as Charley and the Artful Dodger, are almost fated from birth to turn to crime because men like the man in the white waistcoat give them no other options or resources. The death of the man in the white waistcoat suggests that he may be at least as much a criminal as these boys.
The novel repeatedly uses the idea of supernatural forces to foreshadow the great revelation at the end, which is that Oliver is the child of a wealthy man. For example, in Chapter 12, Mr. Brownlow is struck by the eerie resemblance between Oliver and the portrait that turns out to be Oliver's mother:
As [Mr. Brownlow] spoke, he pointed hastily to the picture above Oliver’s head, and then to the boy’s face. There was its living copy,—the eyes, the head, the mouth; every feature was the same. The expression was for the instant so precisely alike, that the minutest line seemed copied with an accuracy which was perfectly unearthly.
Nothing truly magical or "unearthly" happens in Oliver Twist, aside from coincidences. There is a realistic explanation for everything. The fact that Mr. Brownlow gets the feeling that something unearthly is happening, and the fact that the narrator lingers so long over the similarity between Oliver and the woman in the portrait, suggests to the reader that there really is some connection between the two of them that will eventually have an earthly explanation.
Oliver himself appears almost to have a psychic link to Rose Maylie. In Chapter 30, when Oliver is asleep and recovering post-burglary in the Maylie cottage, Rose sheds a tear on his forehead:
The boy stirred and smiled in his sleep, as though these marks of pity and compassion had awakened some pleasant dream of a love and affection he had never known; as a strain of gentle music, or the rippling of water in a silent place, or the odour of a flower, or even the mention of a familiar word, will sometimes call up sudden dim remembrances of scenes that never were, in this life [...] and which some brief memory of a happier existence long gone by, would seem to have awakened [...]
The narrator is careful to note that it looks "as though" Rose's tear conjures for Oliver "dim remembrances of scenes that never were." Again, true supernatural occurrences are not part of the universe of this novel. But the narrator's sentimental lingering over the moment, and the initial appearance of a supernatural connection between Oliver and Rose, signals to the reader that these two have some real significance to one another that is not yet clear. As it turns out, Rose is Oliver's long-lost maternal aunt. These breadcrumbs boost the payoff of the revelation at the end. Not only do all the family connections finally come to light, but the reader also finally has a real-world explanation for what before seemed eerie and impossible.
As early as Chapter 2, the novel foreshadows that a prominent character will die by hanging:
"That boy will be hung," said the gentleman in the white waistcoat; "I know that boy will be hung."
Nobody controverted the prophetic gentleman’s opinion.
Oliver has been a squeaky wheel at the workhouse, asking for more food and asking not to be apprenticed to a cruel man. The man in the white waistcoat sees his failure to comply at all turns as evidence that Oliver will turn into a criminal who will eventually be caught and executed. It seems from this instant that Oliver himself might be hurtling his way toward hanging.
Because of his terrible circumstances, Oliver indeed must sort out whether a life of crime or a life free of crime will result in the greatest chances of survival. Especially once he falls under Fagin's thumb, it seems likely that he will have no choice but to survive through crime until he is caught and hung. Charley Bates reinforces hanging as the fate that awaits criminals, teasing Oliver about this inevitable end in Chapter 18:
Master Bates caught up an end of his neckerchief, and, holding it erect in the air, dropped his head on his shoulder, and jerked a curious sound through his teeth, thereby indicating, by a lively pantomimic representation that scragging and hanging were one and the same thing.
Criminals, such as the ones Oliver and Charley are shaping up to be due to their circumstances, are so sure to meet their end in capital punishment that Charley seems to think they may as well make light of it.
Both the man in the white waistcoat and Charley turn out to be correct that criminality is a long walk to the scaffold. But there is a twist to the end that has been foreshadowed throughout the novel. It is not Oliver who hangs, but rather Sikes, a man who actually commits murder. Oliver's narrow escape from criminality seems to set him on the path for a happy ending. Notably, the man in the white waistcoat also dies before the end of the novel. Although Dickens presents a fairly inflexible view of the fate of those who do go down the path of crime, he raises the question of who ought to be considered a criminal. Some people, such as Charley and the Artful Dodger, are almost fated from birth to turn to crime because men like the man in the white waistcoat give them no other options or resources. The death of the man in the white waistcoat suggests that he may be at least as much a criminal as these boys.
The novel repeatedly uses the idea of supernatural forces to foreshadow the great revelation at the end, which is that Oliver is the child of a wealthy man. For example, in Chapter 12, Mr. Brownlow is struck by the eerie resemblance between Oliver and the portrait that turns out to be Oliver's mother:
As [Mr. Brownlow] spoke, he pointed hastily to the picture above Oliver’s head, and then to the boy’s face. There was its living copy,—the eyes, the head, the mouth; every feature was the same. The expression was for the instant so precisely alike, that the minutest line seemed copied with an accuracy which was perfectly unearthly.
Nothing truly magical or "unearthly" happens in Oliver Twist, aside from coincidences. There is a realistic explanation for everything. The fact that Mr. Brownlow gets the feeling that something unearthly is happening, and the fact that the narrator lingers so long over the similarity between Oliver and the woman in the portrait, suggests to the reader that there really is some connection between the two of them that will eventually have an earthly explanation.
Oliver himself appears almost to have a psychic link to Rose Maylie. In Chapter 30, when Oliver is asleep and recovering post-burglary in the Maylie cottage, Rose sheds a tear on his forehead:
The boy stirred and smiled in his sleep, as though these marks of pity and compassion had awakened some pleasant dream of a love and affection he had never known; as a strain of gentle music, or the rippling of water in a silent place, or the odour of a flower, or even the mention of a familiar word, will sometimes call up sudden dim remembrances of scenes that never were, in this life [...] and which some brief memory of a happier existence long gone by, would seem to have awakened [...]
The narrator is careful to note that it looks "as though" Rose's tear conjures for Oliver "dim remembrances of scenes that never were." Again, true supernatural occurrences are not part of the universe of this novel. But the narrator's sentimental lingering over the moment, and the initial appearance of a supernatural connection between Oliver and Rose, signals to the reader that these two have some real significance to one another that is not yet clear. As it turns out, Rose is Oliver's long-lost maternal aunt. These breadcrumbs boost the payoff of the revelation at the end. Not only do all the family connections finally come to light, but the reader also finally has a real-world explanation for what before seemed eerie and impossible.
In Chapter 40, Nancy goes to Rose Maylie to tell her what she has learned about Oliver through eavesdropping on Monks and Fagin's conversation. Nancy and Rose's conversation ends with Nancy foreshadowing her own death:
I must go back. Whether it is God’s wrath for the wrong I have done, I do not know; but I am drawn back to him through every suffering and ill usage, and should be, I believe, if I knew that I was to die by his hand at last.
It is not abundantly clear whether it is Sikes or Fagin to whom Nancy imagines maintaining her loyalty. She never uses a name because she is protecting everyone involved except for Monks. When Nancy first refuses Rose's offer to protect her from Fagin, Sikes, and the boys, she mentions a "desperate" man she must go back to. It seems likely that she is thinking of Sikes, with whom she is partnered romantically and whom she has left drugged at home to come speak with Rose. But as she continues her refusal of Rose's offer, she says that the man she is thinking of would be sure to die if she gave up the criminals' whereabouts because he is "the boldest, and has been so cruel." Now it seems more likely that Nancy is thinking of Fagin. He, after all, is the head of the whole operation and has orchestrated most of the crimes Sikes and the boys have committed. The ambiguity around who Nancy is talking about emphasizes this moment as an instance of foreshadowing. Ultimately, Sikes and Fagin will both be responsible for her death. Sikes will carry out the actual murder, but Fagin will nudge Sikes into it. The uncertainty about who is drawing Nancy back sets the reader up for later uncertainty about who, exactly, is responsible for her murder.
The foreshadowing also suggests that no matter who ends up killing Nancy, her fate is already sealed by her circumstances. Nancy's unwitting prediction of her own murder can be read as the darker side of Dickens's satire on marriage and family throughout this novel. Although not legally married, Nancy and Sikes are effectively a married couple. Although not biologically related to Nancy, Fagin is effectively her father figure. With the Bumbles and the Sowerberrys, Dickens jokes that marriage and family ties can make people comically unhappy. Nancy's loyalty to her created family leads her beyond comical unhappiness and all the way to an extremely violent end that is wholly predictable. From Rose's perspective, Nancy is probably going to die dimply because she is a poor woman with misguided loyalties to anonymous criminals. If not Sikes or Fagin, someone else would kill her. Tragically, Nancy's redemptive attempt to help Oliver comes too late for her to escape the common fate of any criminal, which in this novel is generally to die a horrible and lonely death.