The Prophet, by Kahill Gibran

For life goes not backwards nor tarries with yesterday

And then a woman who held a babe against her breast said, speak to us of children: and he said, your children are not your children. They are the sons and daughters of life's longing for itself. They come through you but not from you. And though they are with you, yet they belong not to you. You may give them your love, but not your thoughts. They have their own thoughts. You may house their bodies, but not their souls, for their souls dwell in the house of tomorrow which you cannot visit, not even in your dreams. You may strive to be like them but seek not to make them like you. For life goes not backwards nor tarries with yesterday." -- The Prophet, by Kahill Gibran