I'm not sure of the source on this, but this is a story I've heard, and I like it.
An elder Cherokee Native American was teaching his grandchildren about life. He said to them, "A fight is going on inside me. It is a terrible fight, and it is between two wolves. One wolf represents fear, anger, envy, sorrow, regret, greed, arrogance, self-pity, guilt, resentment, inferiority, lies, pride, and superiority. The other wolf stands for joy, peace, love, hope, sharing, serenity, humility, kindness, benevolence, friendship, empathy, generosity, truth, compassion, and faith. This same fight is going on inside of you and every other person too." The children thought about it for a minute and then one child asked his grandfather, "Which wolf will win?" The old Cherokee simply replied: "The one I feed."
This story fits precisely with the argument I make about nurturing the divine spark, the kingdom of God, within each of us. We must take positive steps to take care of this precious gift, and give it a chance to grow and bring light to those around us- and also peace to those around us.