Act Two, Scene I
That same evening, Rachel's father Reverend Brown leads a bible meeting. With the nationally known orator, Brady, seated near him on the platform, Brown launches into a "hellfire and brimstone" speech denouncing Bert and the evil that he has taught. When Rachel attempts to defend Bert, Brown calls for divine retribution against his own daughter. Brady intervenes, advising the overzealous Reverend with the Biblical quotation from Proverbs that provides the play's title: "He that troubleth his own house shall inherit the wind." After the meeting disperses, Brady and Drummond—once good friends and colleagues—speak briefly. Brady asks why their relationship has drifted apart. Drummond responds that maybe it is Brady who has moved away by standing still. This rebuke stuns Brady, literally knocking him off balance as he exits, leaving Drummond alone on stage.
Act Two, Scene II
The trial is in full swing. Howard, a student from Bert's class, is on the witness stand. Brady skillfully manipulates Howard's testimony to favor the prosecution, ending his examination with an impassioned and overtly biased speech against the "evil-lutionsts." Drummond's cross-examination shows the whole point of the defense—Howard, or anyone else, has the right to listen to new ideas and the right to think about what those new ideas mean. Later, Rachel is called to testify. Brady questions Rachel about Bert's faith in God and then manipulates her into repeating Bert's observation that God created Man in His own image, and Man returned the favor. Realizing that everything she says makes Bert appear even more guilty, Rachel breaks down in tears and leaves the witness stand before Drummond can cross-examine her. Brady rests the prosecution's case. Drummond begins the defense by calling three prominent scientists to the stand, but the court rules that their possible testimony is irrelevant to this particular case.
Drummond appears to have no witnesses to testify for the defense. He seizes on the idea that if the court refuses to allow testimony on science or Charles Darwin (the scientist whose work supports the evolution theory), it should allow testimony on the Bible. He calls Brady to the stand as an expert on the Bible, over the objections of D.A. Davenport. At first, Brady fends off Drummond's questions about Biblical events with pious platitudes. As Drummond continues, however, Brady is forced to admit that the first day of creation was "not necessarily a twenty-four hour day." When Drummond gets Brady to admit that he believes God speaks to him, telling him what is right and wrong, the prosecutor's credibility is destroyed. He is left on the stand, ignored, reciting scripture, as the court adjourns for the day.