While guilt is certainly present in Arthur Miller's play The Crucible, I would have a hard time saying that it is a central theme.
The examples of where guilt are seen is John Proctor's guilt for having an affair with Abigail and John Hale's guilt for being a part of the hysteria in Salem.
John Proctor, by the end of the play, can be seen as a man truly sorry for his actions. He wishes to make good on the accusations against his wife by calling out Abigail for what she is: a liar and a woman involved in an adulterous relationship. The fact that Proctor feels guilt for the affair, compacted with the accusations against his wife and friends, forces him to come to terms with his guilt.
As for reverend John Hale, Hale is brought in from another town fro being a noted expert on witches. He comes to Salem to help the townspeople with their problem. In the end, it is his expertise which lends itself to the hysteria and caused the numerous accusations to fly. Hale feels guilty because of his position and supposed knowledge on the subject. He resigns himself from the courts in order to relieve himself of some of the guilt he feels.
In The Crucible, Arthur Miller explores the theme of guilt through the plight of several central characters, as well as the community's reaction to the witch hunt. John Proctor's guilt for having an affair with Abigail Williams is central to the plot of the play. Proctor's guilt affects his personality, relationship, and decisions. Proctor's guilt also motivates him to challenge Abigail in court for ruining his reputation after he learns that she is plotting against his wife. Reverend Hale also feels extremely guilty for accusing people of witchcraft after he discovers that the convictions are unjust and unfounded. Hale believes that he is responsible for stirring up the hysteria in the community that led to the deaths of several respected citizens. By the end of the play, Hale denounces the Court and encourages the accused citizens to lie in their testimonies so that their lives will be spared.
Many of the accused citizens admit to being involved in witchcraft out of guilt. In a strictly religious community such as Salem, guilt motivates individuals to seek redemption. Whether or not these citizens have actually engaged in witchcraft is debatable. Many citizens simply admit to witchcraft because they feel guilty about their other sins, which only adds to hysteria throughout the community.