How does Parris nullify Proctor's testament in Act III?
When John Proctor walked in with Mary Warren, Parris started accusing him of mischief and having plans to overthrow the court. Danforth asked how Mary Warren was alleged attacks by evil spirits, and she confessed to pretending. Mary further stated that the other girls were also pretending. This statement shocked Danforth. Cheever stated that Proctor ripped the warrant as evidence of his disobedience to the court. Parris felt vindicated by this statement. John stated that he was a good Christian after Danforth asked him about it. However, Parris accused him of attending church only once a month.
John confessed to being unfaithful to his wife with Abigail, one of the girls, in order to discredit her testimony. Elizabeth, John’s wife, was called to corroborate his statement, but she failed to confirm it, believing she was saving her husband’s reputation.
Mary Warren was overwhelmed by the girls and turned against John, accusing him of witchcraft. In regards to Mary’s statement, Danforth questioned John about his relationship with the devil to which he responded: “God is dead”. Taking the opportunity, Parris relied on this statement to damn John Proctor as a warlock.
Proctor, his mind wild, breathless: I say - I say - God is dead'
Parris: Hear it, hear it!
When Proctor attempts to prove beyond a doubt that Abigail is motivated by personal aims in her accusations in court, he admits to his affair with Abigail.
The court (Danforth and Parris) want confirmation of Proctor's claims and so call Elizabeth to confirm or deny them. Elizabeth, thinking that she is saving Proctor's honor, lies and says that there was no affair.
This damns Proctor as a liar and serves to undermine his testimony. Not long after this moment, Mary Warren claims that Proctor is the "Devil's man" and he has made her sign a book every night, forcing her also to come and "overthrow the court".
Parris then goads Proctor on to anger. At this point Proctor says, "God is dead" and the court places him under arrest.