Supernatural (2005) : 5x17

Sam and Dean are outnumbered by demons, but are saved at the last minute by Rob and his townspeople, who are aware of the Apocalypse, and have been training to fight and kill demons. The small town is very religious and Sam and Dean meet Pastor Gideon, who introduces them to his daughter Leah, whom he claims is a prophet. Leah tells the townspeople they must obey her orders if they want a spot in Heaven but when she starts turning the townspeople against each other in the name of the Lord, the brothers realize they must kill her.