This sermon warns people who pretend to be good Christians in public but secretly sin in private, explaining that their secret sins are foolish because God sees everything they do, even in the dark. Spurgeon says that living a double life makes people miserable because they constantly worry about being caught, and he warns that secret sins always lead to bigger sins that will eventually be discovered. He urges people to confess their hidden sins to God, give them up completely, and choose to follow Jesus honestly instead of trying to fool others while destroying their own souls.

A sermon delivered by Charles Spurgeon on February 8, 1857.