What we are today comes from our thoughts of yesterday, and our present thoughts build our life of tomorrow: our life is the creation of our mind. If a man speaks or acts with an impure mind, suffering follows him as the wheel of the cart follows the beast that draws the cart. What we are today comes from our thoughts of yesterday, and our present thoughts build our life of tomorrow: our life is the creation of our mind. If a man speaks or acts with a pure mind, joy follows him as his own shadow.

The Dhammapada