Jenny's Faith

 is a mission in Red Dead Redemption.

Story
John finds a very religious woman ill on the side of the road.

Walkthrough
Start the mission by speaking to Jenny. She can be found just outside of Armadillo. She will be marked with a ? when you can start this mission.

She will say she is fine and for you to leave her alone. She obviously is not fine. Head into town and buy medicine from the store.

Bring the medicine back to her.

Overview

You found a sick woman in the wilderness named Jenny. Out of sympathy, you shared some of your medicine with her. Though you offered to take her to town to seek help, she refused, and chose to remain in the wilderness.