When Reverend Hale arrives in Salem to investigate rumours of witchcraft, Giles Corey, probably thinking that he was doing good, asks the reverend to explain Mrs Corey's fascination with strange books. When the reverend tries to tell him that there is no significance in that, he presses the reverend and states that whenever Martha (his wife) reads these tomes, he cannot pray, but that as soon as she stops and walks out, his ability to pray suddenly returns. He states that this oddity 'discomfits' him.

This statement about the stoppage of prayer piques Reverend Hale's interest and he tells Giles that he will later speak to him about it. Giles then declares that he does not believe that his wife is touched by the devil but that he would like to know what she is reading and why she hides her books since she won't tell him. It is clear that Reverend Hale is not much interested in what he has to say at this point because he has more important matters to attend to. He once again promises Giles that they will speak about it later.

In Act lll, it so happens that, unfortunately for Giles, Martha is later arrested on a charge of witchcraft, an accusation brought against her by a man called Walcott. Giles comes to the Proctor's house where he meets Reverend Hale and he then cries out that he had never said that his wife was a witch, only that she had read books.

It is obvious that Reverend Hale did not have a hand in Martha's arrest for he asks Giles exactly what the complaint was against his wife. Giles proceeds to explain that Walcott had charged Martha because the pig he had bought from her died and he wanted his money back. She refused and told him “Walcott, if you haven’t the wit to feed a pig properly, you’ll not live to own many.” He testified to the court that Martha had cursed him with her books because none of the pigs he had bought since that day could stay alive for more than four weeks.

Giles is distraught because he believes that his earlier question to Reverend Hale is part of the reason that she has been incarcerated. He then decides, with John Proctor, whose wife has also been arrested, to go to court and plead her innocence. When Giles has an opportunity to address deputy governor Danforth, who is in charge of proceedings, he breaks down and reasserts the fact that he did not call his wife a witch. He only wanted to know why she was so interested in books because none of his previous two wives were so into reading. He is overwhelmed and starts weeping, stating that he has betrayed his wife.

The unfortunate Giles' efforts to save his wife amounts to nothing because he is later arrested for contempt of court for refusing to provide the name of a witness in an accusation against Mr Putnam. He shouts that he had already given up his wife's name and will not allow an innocent to be arrested again because of him. The charge later becomes one of witchcraft and Giles is later pressed to death when he refuses to confess.

Giles Corey, a character from Arthur Miller's The Crucible, feels guilty about his wife (Martha Corey) being charged with witchcraft. Giles does not think before he speaks. In fact, his quick tongue (speech) gets him into much trouble throughout the play. 

The accusation against Martha Corey stems from Giles' question posed to Reverend Hale. Giles asks Hale, "What signifies the readin’ of strange books?" Unknowingly, by questioning his wife's reading, Giles has just placed her into the path of being accused of witchcraft. It is not until Giles' wife is charged with witchcraft that he realizes the mistake he made earlier when drawing attention to the fact that she read books other then the Bible. 

Giles, when speaking of Martha's arrest, states that he never said Martha was a witch; he only stated that she was reading books. When Hale asks about the charges, Giles tells him that Martha was charged by Walcott for bewitching the pigs with the books she read. With Martha's arrest, Giles states that he "broke charity with her" (his wife). He realizes that it is his fault that she stands accused of witchcraft. If he would not have spoke of Martha reading books, chances are Martha may never have been charged.That said, one could assume that Walcott may have found another way to offer up "proof" of Martha being a witch (in order to blame the death of the pigs upon her).