Buddha says: "Once upon a time, there were two monks who went on a pilgrimage across the country together. One day, they came to a river back and saw a beautiful girl who was unable to cross the river.
Seeing her difficulty, the elder monk volunteered to carry her across the river on his back while the younger one looked on in consternation.
When the sun went down, the monks came upon a dilapidated shack and decided to stay there for the night. The elder monk quickly fell asleep while the younger one twisted around, unable to calm his mind. Finally, he woke up the elder monk and reprimanded him for what happened during the day, "As monks, we are supposed to keep away from women. I am really ashamed and troubled by what you did today!"
The elder monk looked at his friend and a smile broke up on his face, "Oh, so that has been bothering you! Brother, I have left the girl behind by the river bank, why are you still carrying her around?"