PROCTOR: But the proof, the proof!
MARY WARREN: I told you the proof. It’s hard proof, hard as rock, the judges said.
– Arthur Miller
The Crucible, Act 2. John Proctor is rightfully doubtful of the "proof" against the beggar Sarah Good that she is guilty of witchcraft. But his servant Mary Warren sides with the court, which earlier that day condemned Osburn because Mary testified that she "mumbled" to her and she could not recite her ten commandments for the judges. Mary uses an ironic simile to compare the non-existent proof against Good to "hard as rock." This is an example of the unfair justice being meted out to the accused in the Salem witch trials.