hetuḥ

कर्मण्येवाधिकारस्ते मा फलेषु कदाचन

hetuḥ — cause

Your right is to the action alone, never to its fruits. Do not act for the sake of the fruit, and do not be attached to inaction either.

ऋषिभिर्बहुधा गीतं छन्दोभिर्विविधैः पृथक्

hetu-madbhiḥ — with logic

It has been sung by the seers in many ways, in various hymns, and in the aphorisms on Brahman, with reasoning.

कार्यकारणकर्तृत्वे हेतुः प्रकृतिरुच्यते

hetuḥ — the medium

Nature is said to be the ground of cause and effect and of doing; the person is said to be the ground of the experience of pleasure and pain.