Throughout the ages false prophets have existed right alongside true prophets.  Sometimes the false prophet arrives after the true one to challenge the message of the true prophet.  Sometimes the false prophet comes before the true, in which case, the true is sent to expose his falsity.  The false prophet would like to operate without being recognized as false.  He, being unchallenged, feels secure in his own message; in an odd way, the message becomes believable to himself.  He does not want anyone showing up with the light of truth on him.  He peddles deception; we must be careful lest we are deceived by him.

“And many false prophets will arise and lead many astray” (Matthew 24:11 ESV).