From Ray Comfort, who responds to the notion that people should do good, not because of fear of punishment for bad actions or because they’re told to, but for the sake of goodness:
However, such idealism is unrealistic. We are sinners with desperately wicked hearts, and we are incapable of such noble motives.
I’m not sure if that constitutes a bit of a grim peak at Ray’s moral compass, there. For one, I can assure you that whenever I try to help someone, it isn’t because I was told to (well, usually) or because I fear any sort of reprimand for not doing so. It’s because I genuinely care about whomever I’m trying to help out and receive a feeling of gratification whenever I further a cause I believe in, or just when I make someone smile in appreciation. It’s a basic part of human nature, and a damn good one, too.
If you really believe that you only commit good deeds for the promise of reward, then that indicates that you don’t personally care about doing good or helping people – or worse still, that you only refuse to commit evil deeds out of a fear of punishment, not because you feel that it’s wrong.
And people like that scare me. It’s a definition of sociopathy.