One evening an old Cherokee told his grandson about a battle that goes on inside people. He said, "My son, the battle is between 2 wolves" inside us all. One is Evil. It is anger, envy, jealousy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority,lies, false pride, superiority, and ego.

The other is Good. It is joy, peace, love, hope, serenity,humility, kindness, benevolence, empathy,
generosity, truth, compassion and faith."

The grandson thought about it for a minute and then asked his grandfather:
"Which Wolf Wins?"
The old Cherokee simply replied, "The One You Feed."

I wouldn't preach it (cheese factor is too high) but it's a good visual for sinful nature vs. Holy Spirit and how our free will affects the outcome.