Bhagavad Gita · Dhyana Yoga (Atma-samyama Yoga)Chapter 6, Shloka 4 (6.4)

Two clingings, one root. Objects (enjoyment) and actions (the pride of doing) — the root of clinging to both is sankalpa.

Shankaracharya — all sankalpas, all desires, all actions. Karmasu ca nitya-naimittika-kāmya-pratiṣiddheṣu prayojanābhāva-buddhyā na anuṣajjate — does not cling to any actions — obligatory, occasional, desire-driven or forbidden — with the understanding "they serve no purpose"; sarvān saṃkalpān ihāmutrārtha-kāma-hetūn — the disposition to give up all sankalpas that cause desires for this world and the next. Then the argument: saṃkalpa-mūlā hi sarve kāmāḥ — sankalpa is the root of all desires; the Mahabharata (Śānti 177.25): kāma jānāmi te mūlaṃ saṃkalpāt kila jāyase — "O desire, I know your root: you are born of sankalpa"; and na hi sarva-saṃkalpa-saṃnyāse kaścit spanditum api śaktaḥ — if all sankalpas fall away, no one can even stir. So sarvān kāmān sarvāṇi karmāṇi ca tyājayati bhagavān — here the Lord has one give up all desires and all actions.

Acharya Ramanuja — the disposition of experiencing the self. Yadā ayaṃ yogī ātmaikānubhava-svabhāvatayā indriyārtheṣu ātma-vyatirikta-prākṛta-viṣayeṣu … na anuṣajjate — when experiencing the self has become one's very nature and there is no clinging to the objects of prakriti, then one has ascended to yoga. Therefore ārurukṣoḥ … tad-ananuṣaṅgābhyāsa-rūpaḥ karma-yoga eva niṣpatti-kāraṇam — for the one climbing, karma yoga in the form of practising non-clinging to objects is the means.

The difference (clear): Shankara — one who has ascended to yoga = one who has renounced all action; Ramanuja — one who has ascended to yoga = one whose nature has become the experience of the self, and karma yoga is the means up to that point.