36. Let the wise man guard his thoughts, for they are difficult to perceive, very artful, and they rush wherever they list: thoughts well guarded bring happiness.
37. Those who bridle their mind which travels far, moves about alone, is without a body, and hides in the chamber (of the heart), will be free from the bonds of Mâra (the tempter).
38. If a man’s thoughts are unsteady, if he does not know the true law, if his peace of mind is troubled, his knowledge will never be perfect.
39. If a man’s thoughts are not dissipated, if his mind is not perplexed, if he has ceased to think of good or evil, then there is no fear for him while he is watchful.
DHAMMAPADA, Chapter 3. Thought