Performing an act of kindness is a tonic for the one who performs it. It is a cornerstone of my faith, just as our bodies are made so that certain foods and certain habits are healthy and others are unhealthy, so are our souls made so that certain kinds of behavior nourish the soul and other kinds are toxic. Human beings were fashioned to be friendly, honest, and helpful to each other. When we act that way, when we resist temptation, when we go out of our way to do a favor for someone, we feel right. Something inside us says, "Yes, this is the way a person is meant to feel." When we are deceitful or jealous, we are acting against our nature, and we have to work hard to resist the message our bodies and souls try to send us.

Harold S. Kushner, Practice Random Acts of Kindness by Editors of Random Acts of Kindness