Bhagavad Gita · Karma YogaChapter 3, Shloka 33 (3.33)

The power of one's nature. This verse is a realistic description of human nature — conditioning and habits run deep, and they do not change merely by saying "no".

Shankaracharya — and a big question. Prakriti = the impressions of past merit and sin that show themselves in this birth; jñānavān api … kiṃ punar mūrkhaḥ — even the wise follow it, to say nothing of the foolish. Nigrahaḥ niṣedha-rūpaḥ kiṃ kariṣyati mama vā anyasya vā — what will restraint in the form of prohibition achieve, whether mine or anyone else's? Then Shankara himself raises a doubt: if everyone simply follows their nature, then is there no room left for puruṣakāra (personal effort, free will), and does scripture become useless? The answer is the next verse (3.34).

Acharya Ramanuja: Scripture says: constantly contemplate the nature of the self as distinct from prakriti — even knowing this, the wise person still strives among material objects according to their nature, that is, their prācīna-vāsanā (old latent tendencies). Over beings who follow beginningless tendencies, what can śāstra-kṛto nigrahaḥ — the prohibition laid down by scripture — achieve? For Ramanuja this is proof of the difficulty of jnana-yoga — hence karma-yoga.