BhG 3.36

syntax

arjuna (Arjuna) uvāca (he spoke):
he vārṣṇeya (O descendant of Vṛṣṇis!),
atha (now) kena (why?) anicchan api (even not desiring) prayuktaḥ [san] (being engaged) ayam puruṣaḥ (such a person) balāt (by force) niyojitaḥ iva (as if engaged) pāpam (to sin) carati (he moves).

grammar

arjunaḥ	–	arjuna 1n.1 m. – white, clear, Arjuna;
uvāca	–	√vac (to speak) Perf. P 1v.1 – he spoke;
atha	–	av. – then, now, moreover, certainly, rather;
kena	–	kim sn. 3n.1 m. – by what?, why?;
prayuktaḥ	–	pra-yukta (pra-√yuj – to yoke, to join, to engage) PP 1n.1 m. – yoked, endowed with, engaged, suitable;
ayam	–	idam sn. 1n.1 m. – this;
pāpam	–	pāpa 2n.1 n. – evil, sin;
carati	–	√car (to move, to go) Praes. P 1v.1 – he moves, he lives;
pūruṣaḥ	–	pūruṣa 1n.1 m. – a person (from: √pur – to precede, to lead or √pṝ – to fill, to nourish, puru – abundance, pūru – people, puruṣa – a person);
anicchan	–	an-icchant (√iṣ – to desire) PPr 1n.1 m. –  [while] not desiring, unwillingly;
api	–	av. – although, moreover, besides, even;
vārṣṇeya	–	vārṣṇeya 8n.1 m. – O descendant of Vṛṣṇis;
balāt	–	av. – by force (from: bala – strength, force; ablative);
iva	–	av. – like, in the same manner as, almost, exactly;
niyojitaḥ	–	ni-yojita (ni-√yuj – to join, to engage) caus. PP 1n.1 m. – joined, engaged;

textual variants

api → iva / nāpi (as if / even not);
anicchann api vārṣṇeya → anicchamānopi balād (even not desiring by force);
balād iva → balād api / ākramyeva (even by force / as if after coming);

Śāṃkara

The key:
an excerpt from the commented verse
quotes from the scriptures
starting polemic

Desire is the enemy of man. Though the source of evil has been pointed out in 2.62, &c., and in 3.34, yet with a view to elicit a concise and clear statement of what was but desultorily and vaguely expressed, – for, the exact cause being known, he might exert himself to exterminate it, – Arjuna asks:		yadyapi anartha-mūlaṃ dhyāyato viṣayān puṃsa (BhG 2.62) iti rāga-dveṣau hy asya paripanthinau (BhG 3.34) iti coktam | vikṣiptam anavadhāritaṃ ca tad uktam | tat saṃkṣiptaṃ niścitaṃ ca idam eveti jñātum icchan arjuna uvāca jñāte hi tasmin tad-ucchedāya yatnaṃ kuryām iti
Arjuna said: But by what dragged on, O Vārshṇeya, does a man, though reluctant, commit sin, as if constrained by force?		arjuna uvāca atha kena prayukto ’yaṃ pāpaṃ carati pūruṣaḥ |anicchann api vārṣṇeya balād iva niyojitaḥ ||3.36||
Dragged on and constrained: as a servant by the king. Vārshṇeya: one born in the family of the Vṛṣṇis.		atha kena hetu-bhūtena prayuktaḥ san rājñeva bhṛtyo ’yaṃ pāpaṃ karma carati ācarati pūruṣaḥ puruṣaḥ svayam anicchann api he vārṣṇeya vṛṣṇi-kula-prasūta balād iva niyojito rājñevety ukto dṛṣṭāntaḥ ||3.36||

Rāmānuja

athāyaṃ jñānayogāya pravṛttaḥ puruṣaḥ svayaṃ viṣayān anubhavitum anicchann api kena prayukto viṣayānubhavarūpaṃ pāpaṃ balān niyojita iva carati

Śrīdhara

tayor na vaśam āgacchet [Gītā 3.34] ity uktam | tad etad aśakyaṃ manvāno ‚rjuna uvāca atheti | vṛṣṇer vaṃśe avatīrṇo vārṣṇeyaḥ | he vārṣṇeya ! anartha-rūpaṃ pāpaṃ kartum icchann api kena prayuktaḥ prerito ‚yaṃ puruṣaḥ pāpaṃ carati ? kāma-krodhau viveka-balena niruddhato ‚pi puruṣasya punaḥ pāpe pravṛtti-darśanāt | anyo ‚pi tayor mūlabhūtaḥ kaścit pravartako bhaved iti sambhāvanayā praśnaḥ

Madhusūdana

tatra kāmya-pratiṣiddha-karma-pravṛtti-kāraṇam apanudya bhagavan-matam anuvartituṃ tat-kāraṇāvadhāraṇāya arjuna uvāca atheti | dhyāyato viṣayān puṃsaḥ ity ādinā pūrvam anartha-mūlam uktam | sāmprataṃ ca prakṛter guṇa-saṃmūḍhā ity ādinā bahu-vistaraṃ kathitam | tatra kiṃ sarvāṇy api sama-prādhānyena kāraṇāni | athavaikam eva mukhyaṃ kāraṇam itarāṇi tu tat-sahakārīṇi kevalam | tatrādye sarveṣāṃ pṛthak pṛthaṅ nivāraṇe mahān prayāsaḥ syāt | antye tv ekasminn eva nirākṛte kṛta-kṛtyatā syād ity ato brūhi me kena hetunā prayuktaḥ prerito ‚yaṃ tvan-matānanuvartī sarva-jñāna-vimūḍhaḥ puruṣaḥ pāpam anarthānubandhi sarvaṃ phalābhisandhi-puraḥ-saraṃ kāmyaṃ citrādi śatru-vadha-sādhanaṃ ca śyanādi pratiṣiddhaṃ ca kalañja-bhakṣaṇādi bahu-vidhaṃ karmācarati svayaṃ kartum anicchann api na tu nivṛtti-lakṣaṇaṃ parama-puruṣārthānubandhi tvad-upadiṣṭaṃ karmecchann api karoti | na ca pāratantryaṃ vinetthaṃ sambhavati | ato yena balād iva niyojito rājñeva bhṛtyas tvan-mata-viruddhaṃ sarvānarthānubandhitvaṃ jānann api tādṛśaṃ karmācarati tam anartha-mārga-pravartakaṃ māṃ prati brūhi jñātvā samucchedāyety arthaḥ | he vārṣṇeya vṛṣṇi-vaṃśe man-mātāmaha-kule kṛpayāvatīrṇeti sambodhanena vārṣṇeyī-suto ‚haṃ tvayā nipekṣaṇīya iti sūcayati

Viśvanātha

yad uktaṃ rāga-dveṣau vyavasthitāv [Gītā 3.34] ity atra śāstra-niṣiddhe |pīndriyārthe para-strī-sambhāṣaṇādau rāga ity atra pṛcchati atheti | kena prayojaka-kartrānicchann api vidhi-niṣedha-śāstrārtha-jñānavattvāt pāpe pravartitum icchā-rahito ‚pi balād iveti prayojaka-preraṇa-vaśāt prayojyasyāpīcchā samyag utpadyate iti bhāvaḥ

Baladeva

indriyasya ity ādau śāstra-niṣiddhe ‚pi para-dāra-sambhāṣaṇādau rāgo vyavasthita iti yad uktaṃ tatrārjunaḥ pṛcchati atha keneti | he vārṣṇeya vṛṣṇi-vaṃśodbhava ! śubhādibhyaś ceti prayuktaḥ preritaḥ pāpaṃ carati niṣedha-śāstrārtha-jñānāt tac-caritam anicchann api balād iveti | prayojakecchāpannatayā prayojye ‚pīcchā prajāyate | sa kim īśvaraḥ, pūrva-saṃskāro vā ? tatrādyaḥ sākṣitvāt kāruṇikatvāc ca na pāpe prerakaḥ | na ca paro jaḍatvād iti praśnārthaḥ