What harm comes being deceived by a false prophet?
Matthew 24:24 says: "For false messiahs and false prophets will appear and perform great signs and wonders to deceive, if possible, even the elect."
Ignoring for a moment the issue of false Christs, I'd like to focus on false prophets.
What happens when a people follow a false prophet? Many Christians view Mormons and Jehovah's Witnesses as having been led away by a false prophet. Where is the harm in this?