What is Hale's mission in Act 4 of "The Crucible"?

Rev. Hale is devastated that so many people have been executed or are waiting in prison, accused of witchcraft. In Act IV, his mission is to put a stop to the executions and accusations. He finally begins telling people to lie and save their lives. He becomes so fanatical in his desire to save people from the gallows that he loses all credibility with Danforth. As he himself says, “I come to do the Devil’s work. I come to counsel Christians they should belie themselves.” Then he brings Elizabeth to try to convince John to sign a confession. When John refuses to sign the confession, Hale turns once again to Elizabeth who, understanding what John's good name means to him, simply says,"“He have his goodness now. God forbid I take it from him!” Hale begins to weep because all his good intentions came too late