In Act III of The Crucible, Danforth informs John Proctor that his wife, Elizabeth, is pregnant. Since she has been in jail since Abigail accused her of sending her spirit out and stabbing her in the stomach. While doctors say that they cannot find any signs that she is pregnant, John tells the court that Elizabeth cannot lie, so if she says she is pregnant she must be. This becomes important late in the act when Danforth questions Elizabeth on John and Abigail’s affair. When asked if she has any knowledge of John committing lechery, she lies for her husband.
In her life, sir, she have never lied. There are them that cannot sing, and them that cannot weep—my wife cannot lie. I have paid much to learn it, sir.