Bhagavad Gītā Chapter Four verse 17

कर्मणो ह्यपि बोद्धव्यं बोद्धव्यं च विकर्मणः ।
अकर्मणश्च बोद्धव्यं गहना कर्मणो गतिः ॥ १७ ॥

karmaṇo hyapi boddhavyaṃ boddhavyaṃ ca vikarmaṇaḥ |
akarmaṇaśca boddhavyaṃ gahanā karmaṇo gatiḥ ||

karman - act, action, performance; work, labour, activity; any religious act or rite; organ of sense

Commentaries and Reflections

Commentary by TKV Desikachar:

“Karma is the means to know oneself.”