In BG 17.25, Arjuna heard that the transcendentalists seeking liberation perform various acts of sacrifice, austerity, and charity, not aiming for some mundane result with the chanting of the sound, tad. Those who are thus seeking liberation are naturally on the path of renunciation (or sannyāsa). This connection between sannyāsa and liberation was established explicitly in BG 9.28. Arjuna also recollects Krishna’s advice in BG 12.11: we should act giving up (or tyāga) all the results of our work, taking shelter of a form of yoga with Krishna and thus try to be self-situated. Arjuna wants to know the distinction between renunciation (sannyāsa) and giving up (tyāga).
The Bhagavad Gita has been revolving around one fundamental question, which Arjuna had asked in chapter 2, chapter 3, and chapter 5, albeit framed differently, and now again he is bringing it back in chapter 18 – what should we really give up on the path to perfection – the action itself or the fruit of action?
Once and for all, Arjuna desires (icchāmi) to distinctly (pṛthak) know (veditum) the truth (tattvam) about renunciation (sannyāsasya) and giving up (tyāgasya). (BG 18.1) The renunciation (nyāsaṁ) of actions (karmaṇāṁ) that are based on selfish material desires (kāmyānāṁ) is what the learned (kavayo) know (viduḥ) as renunciation (sannyāsaṁ). The giving up of the results of all actions (sarva-karma-phala-tyāgaṁ) is what the seers (vicakṣaṇāḥ) call (prāhus) giving up (tyāgaṁ). (BG 18.2) Note that Krishna uses the exact same phrase in BG 12.11: sarva-karma-phala-tyāgaṁ.
There are diverse opinions on the topic of giving up. Some (eke) sages (manīṣiṇaḥ) declare (prāhur) that action (karma) should be given up (tyājyaṁ) considering it as faulty (doṣa-vad ity), while others (cāpare) maintain that acts of sacrifice, charity, and austerity (yajña-dāna-tapaḥ-karma) should never be given up (na tyājyam iti). (BG 18.3) Krishna now wants us to hear (śṛṇu me tatra) His conclusion (niścayaṁ) about giving up (tyāge). The giving up (tyāgo hi) is described (samprakīrtitaḥ) to be of three kinds (tri-vidhaḥ). (BG 18.4)
Before delineating the three kinds of giving up, Krishna first reiterates on some general principles. Acts of sacrifice, charity, and austerity (yajña-dāna-tapaḥ-karma) must not to be given up (na tyājyaṁ kāryam eva tat). In fact, sacrifice, charity, and austerity (yajño dānaṁ tapaś ca) purify (pāvanāni) even (eva) the great sages (manīṣiṇām). (BG 18.5) But (tu), furthermore (api), all these (etāny) activities (karmāṇi) should be performed (kartavyānīti) giving up (tyaktvā) attachment (saṅgaṁ) and fruits [or results] (phalāni ca). That is Krishna’s (me) final (niścitaṁ) transcendental (uttamam) opinion (matam). (BG 18.6)