In The Crucible, Hale asks John to recite the Ten Commandments and he can't recite all of them. Elizabeth must complete the list by citing the prohibition against adultery. What is the irony?...
In The Crucible, Hale asks John to recite the Ten Commandments and he can't recite all of them. Elizabeth must complete the list by citing the prohibition against adultery. What is the irony? And what's the purpose?
The purpose that Reverend Hale has in asking John Proctor to recite the Ten Commandments is to test him on his degree of faith. He does not attend church regularly, is very outspoken about how he dislikes Reverend Parris, and because of this dislike, he has not had his last child baptized.
Reverend Hale is at the Proctor's home because he is investigating the members of the community to get a better understanding of the people to determine how bad the witchcraft scandal in the town really is. And, because Elizabeth Proctor's name has been mentioned in court that day.
When John Proctor is interviewed, or interrogated, he is asked to recite the Ten Commandments, and he can't remeber the commandment against committing adultery.
Irony is when the outcome is different than what is expected. It is ironic, because he has committed adultery, with Abigail Williams. He should know this commandment better than the other nine. So it is ironic, since the reader would expect him to know it, and he can't remember it.
Elizabeth knows that John committed adultery, so this moment in the play makes Proctor very self-conscious. His lack of knowledge in the faith and his lack of church attendance and the fact that he has openly criticized the Pastor of the church put him in a suspicious light.
Reverend Hale believes that "Theology [...] is a fortress; no crack in a fortress may be accounted small." He chastises John Proctor for John's apparent lack of conformity to the doctrine of their Puritan faith. Puritans had to go to meetinghouse each Sunday; they had to have their children christened in the church, and they had to understand and properly interpret their core document, the Bible. Hale's purpose, then, in asking John to recite the Ten Commandments is to test John's devotion to the faith -- he ought to have such a basic list committed to memory if he is a true believer. Mary Warren had even told Elizabeth at the beginning of the act that an inability to recite the Commandments had been used as evidence against one of the accused in court. This helps us to understand how basic the memorization of these rules is to their faith.
It is ironic that John forgets the commandment concerning adultery because, as the other commenter wrote, we would expect him to remember the one that he broke so recently and to the detriment of his relationship with his wife.