Bhagavad Gita · Karma Sannyasa YogaChapter 5, Shloka 13 (5.13)

The city and its king. The body is a city with nine gates and all kinds of citizens (the senses, the mind) — and the self is its king, who lives happily, neither doing anything himself nor making others do it.

Shankaracharya — renunciation "manasā" (with the mind). Sarvāṇi karmāṇi … nityaṃ naimittikaṃ kāmyaṃ pratiṣiddhaṃ ca … manasā viveka-buddhyā karmādau akarma-sandarśanena saṃtyajya — renouncing all actions — daily, occasional, desire-driven and forbidden — with the mind, with discerning intellect, seeing inaction in action; tyakta-vāṅ-manaḥ-kāya-ceṣṭaḥ nirāyāsaḥ prasanna-cittaḥ — having given up the activity of speech, mind and body, effortless, with a serene mind, sukham āste. Shankara then raises a question: every embodied being lives in a body anyway, so is it pointless to say "in the city of nine gates"? Answer: the ignorant person is deha-indriya-saṅghāta-mātrātma-darśī — takes the aggregate of body and senses to be the self, and so thinks of himself as living "in a house, on the ground"; the wise one knows that he lives in the body, and is not the body.

Acharya Ramanuja: ātmanaḥ prācīna-karma-mūla-deha-sambandha-prayuktam idaṃ karmaṇāṃ kartṛtvaṃ na svarūpa-prayuktam iti viveka-viṣayeṇa manasā — with the discerning understanding that this doership comes from the connection with a body formed by past karma, not from one's own nature, one renounces all actions into the city of nine gates (the body), and svayaṃ dehādhiṣṭhāna-prayatnam akurvan dehena naiva kārayan — neither oneself making the effort of running the body, nor making the body act — lives happily.