Bhagavad Gita · Karma YogaChapter 3, Shloka 8 (3.8)

Three arguments. (1) Action is superior to inaction; (2) without action even the body will not keep going; (3) (in the next verse) make action a yajña, and it does not bind.

Shankaracharya: dṛṣṭaḥ karmākarmaṇor viśeṣo loke — the difference between action and inaction is plain to see in the world itself: without work, not even the body keeps going. And the next verse answers the notion that action causes bondage and should therefore not be done.

Acharya Ramanuja — karma-yoga is better even than jnana-nishtha. Action is suśaka (easy) and asambhāvita-pramāda (with little chance of error); so even for one eligible for jnana-nishtha, karma-niṣṭhā eva jyāyasī — steadfastness in action is better. And while acting, contemplation of one's own akartritva (that I am not the real doer), from true knowledge of the self, goes along with it — that is, ātma-jñānasya api karma-yogāntargatatvāt — knowledge of the self is itself included within karma-yoga. On the maintenance of the body Ramanuja says: even for jnana-nishtha the body has to be kept going, and that should be done with nyāyārjita-dhana (honestly earned wealth), by performing the great yajñas and so on and living on what remains (prasad) — quoting the Chhandogya saying āhāra-śuddhau sattva-śuddhiḥ (when food is pure, the inner being is pure).