Throughout the novel, O'Connor puts great emphasis on eyes and blindness. The narrator pays close attention to what the characters' eyes look like and what they're looking at, and the characters frequently seem bothered when other characters gaze at them. The characters are also bothered when other characters suggest that they can't see clearly, which introduces a distinction between literal sight and a more spiritual or metaphysical kind of sight. Through this motif, O'Connor foreshadows Hazel's self-inflicted blindness at the end of the novel.
When a new character is introduced, the narrator often describes their eyes by way of comparisons. Over the course of the novel, characters' eyes are likened to pecans, bottle glass, fleas, quicksand, mud, bullet holes, slate, and ice. Additionally, the narrator repeatedly describes characters being watched by eyes. Sometimes, the eyes look at each other.
In the fifth chapter, Hazel is perturbed by the experience of an owl watching him with one eye—so much so that he talks to it. When Enoch meets Gonga the Gorilla and thinks he's about to look into a pair of animal eyes, he's horrified to see "an ugly pair of human ones." The humiliation of this moment is part of what compels him to commit murder later in the novel. Meeting the gaze of the other represents the uncomfortable experience of discovery and truth. Just as looking into the Gonga's eyes reveals to Enoch that he isn't dealing with a real gorilla, Hazel discovers that Asa Hawks's blindness is fake when he sneaks into his room, lights a match, and their "two sets of eyes [look] at each other."
The characters often seem disturbed by each other's gazes. When Hazel and Sabbath meet for the second time, for example, he charges her with giving him "fast eye." The third time they meet, she reverses the charge: "It was you give me the eye." Ironically, it turns out that Hazel's eyes are exactly what draws Sabbath to him: "I like his eyes. [...] They don't look like they see what he's looking at but they keep on looking."
This idea of eyes that can't see appears repeatedly in the novel. To begin with, there are multiple blind (or seemingly blind) characters, such as Asa Hawks, Enoch's landlady, and eventually Hazel himself. When Hazel and Hawks first meet in the third chapter, Hawks claims that Hazel's "got eyes and see not." Hazel becomes fixated on proving that he can see, and he cries out to the crowd, "Don't I have eyes in my head? Am I a blind man?" In the novel's early chapters, he uses eyesight as praise, like when he tells the one-armed man that his car was "built by people with their eyes open." He also claims his church is one in which "the blind don't see." Hazel's obsessions with sight and blindness, as well as other characters' claims that he can't see, foreshadow his blindness at the end of the novel.
Eventually, even if he discovers that Hawks is merely feigning his blindness, Hazel seems to conclude that Hawks is right in suggesting that he can't see. In the Chapter 14, after he's blinded himself, he ironically suggests to Mrs. Flood that she can't see. In these moments, O'Connor explores the weighty symbolism of sight and blindness in Christianity. Hazel believes he only becomes capable of sight after he is blind. Although Mrs. Flood "liked to see things," she gradually accepts his claim that he sees things that she can't see: "To her, the blind man had the look of seeing something."
Over the course of Chapter 5, O'Connor uses foreshadowing and dramatic irony to build the tension and excitement. In this chapter, both Enoch and Hazel have plans that they intend to execute on. Enoch is especially eager, as he is driven by a sense of inevitability as well as a fierce intuition—which he refers to as his "wise blood."
At the very end of Chapter 4, the reader already begins to sense that the action will rise in the following chapter—and that it will have something to do with an interaction between Hazel and Enoch. This is because Hazel asks another driver where the zoo is and says “I got to see a boy that works in it." Earlier in the novel, Enoch told Hazel that he works at the zoo.
In the opening of the fifth chapter, the narrator builds on the foreshadowing from the end of Chapter 4:
That morning Enoch Emery knew when he woke up that today the person he could show it to was going to come. He knew by his blood. He had wise blood like his daddy.
The opening of the chapter is marked by both dramatic irony and foreshadowing. Although Enoch doesn't yet seem to know who "the person" he's waiting for is, the reader knows that this person is Hazel Motes. The repetition of the word "knew" and the dramatic tone of these sentences signals that whatever comes of their interaction will be significant to the overall plot development.
As the chapter proceeds, the foreshadowing continues. While remaining in the third person, the narration closely follows Enoch's perspective. He's fixated on an unspecified mystery, and he's urgently waiting for a "special person" whom he can show it to: "He knew he would know him when he saw him and he knew that he would have to see him soon or the nerve inside him would grow so big that he would be forced to steal a car or rob a bank or jump out of a dark alley onto a woman."
While the reader doesn't yet know what Enoch's mystery is, the reader does know who the special person is. The interplay between the previous chapter and this chapter makes it quite clear that the reader will discover the form and contents of this mystery at the same time as Hazel.
Over the course of the chapter, the narrator repeatedly refers to Enoch's "wise blood," or instinct. Enoch seems to have gotten this expression from his father. He has a mixed relationship to his wise blood: on the one hand he wants to resist it, on the other hand he believes he can't help but go along with what it tells him to do. Moreover, he sees his wise blood as dangerous, as it tends to drag him into trouble: "it’s always something against the law." Enoch seems to understand his life in terms of destiny and inevitability, and he doesn't seem to believe he has much free will. By choosing the title Wise Blood, O'Connor underlines that the novel is about the torture of faith and instinct. The title also seems to mock Enoch, since he isn't particularly wise.
As the chapter proceeds, the reader becomes more and more certain that Enoch's mystery will influence the rest of the novel—and that this influence will bring the characters into dark or dangerous territory. O'Connor picks this foreshadowing back up later in the novel, when Enoch becomes sure that "the thing that was going to happen to him has started to happen."