Mind is the forerunner of all actions. All deeds are led by mind, created by mind.
If one speaks or acts with a corrupt mind, suffering follows, as the wheel follows the hoof of an ox.
If one speaks or acts with a serene mind, happiness follows, as a shadow that never departs.
— Dhammapada, Verse 1–2
(Yamaka Vagga — "The Pairs"; Pali Canon, Khuddaka Nikāya)