Mind precedes all mental states. Mind is their chief; they are all mind-wrought. If with an impure mind a person speaks or acts, suffering follows him like the wheel that follows the foot of the ox.

The Dhammapada begins not with a deity or a doctrine but with a description of cause. Mind comes first; the world follows. The image is deliberately agricultural — the wheel of an ox-cart pressing into the rut behind the animal's hoof. There is no scolding here. The verse does not say impurity is wrong. It says impurity is heavy and that it leaves a mark in the road behind you. The teaching is observational, not moral. The work, accordingly, is not to fight the mind but to watch what it is leaving in its track.