(35) Hard it is to train the mind, which goes where it likes and does what it wants. But a trained mind brings health and happiness. (36) The wise can direct their thoughts, subtle and elusive, wherever they choose: a trained mind brings health and happiness.
(360) Train your eyes and ears; train your tongue and nose. The senses are good friends when they are trained. (361) Train your body in deeds, train your tongue in words, train your mind in thoughts. This training will take you beyond sorrow.
– The Dhammapada