BhG 13.20

syntax

kārya-kāraṇa-kartṛtve (in the state of being cause, effect and the doer) prakṛtiḥ (nature) hetuḥ ucyate (it is called the reason).
puruṣaḥ (a person) sukha-duḥkhānāṁ (of pleasure and distress) bhoktṛtve (in enjoying) hetuḥ ucyate (he is called the reason).

grammar

kārya-kāraṇa-kartṛtve	–	kārya-kāraṇa-kartṛtva abst. 7n.1 n.; DV / TP: kāryasya ca karaṇānām ca kartṛtva iti – in being the doer of cause and effect (from: √kṛ – to do, kārya – to be done, work, duty, especially religious one; karaṇa – deed, direct cause, instrument, helper, kāraṇa – cause, motive, principle, the means; √kṛ – to do kartṛ – a doer); or DV: kāryatve ca kāraṇatve ca kartṛtve ceti – in effect, in cause and in being the cause;
hetuḥ	–	hetu 1n.1 m. – cause, motive, reason;
prakṛtiḥ	–	prakṛti 1n.1 f. – nature, primary substance, original cause (from: pra-√kṛ – to produce);
ucyate	–	√vac (to speak) Praes. pass. 1v.1 – it is said;
puruṣaḥ	–	puruṣa 1n.1 m. – a person (from: √pur – to precede, to lead or √pṝ – to fill, to nourish, puru – abundance, pūru – people);
sukha-duḥkhānāṁ	–	sukha-duḥkha 6n.3 m.; DV: sukhānāṁ ca duḥkhānāṁ ceti – of pleasure and distress (from: su – prefix: good, excellent, beautiful, virtuous; kha – cavity, hole, nave; su-kha – joy, happiness; dur / dus – prefix: difficult, bad, hard; duḥ-kha – pain, difficulty; literally: good or bad hole in the nave [of a wheel through which an axis runs] that makes the moving smooth or not; or from: su-√sthā and duḥ-√sthā);
bhoktṛtve	–	bhoktṛtva abst. 7n.1 n. – in the state of being the enjoyer (from: √bhuj – to eat, to enjoy, bhoktṛ – one who eats, enjoys);
hetuḥ	–	hetu 1n.1 m. – cause, motive, reason;
ucyate	–	√vac (to speak) Praes. pass. 1v.1 – it is said;

textual variants

kārya-kāraṇa-kartṛtve → kārya-karaṇa-kartṛtve (in effect, in direct cause and in being the cause);

Śāṃkara

ke punas te vikārāḥ guṇāś ca prakṛti-saṃbhavāḥ ? ity āha —
kārya-karaṇa-kartṛtve—kāryaṃ śarīraṃ karaṇāni tat-sthāni trayodaśa | dehasyārambhakāṇi bhūtāni pañca viṣayāś ca prakṛti-saṃbhavāḥ vikārāḥ pūrvoktā iha kārya-grahaṇena gṛhyante | guṇāś ca prakṛti-saṃbhavāḥ sukha-duḥkha-mohātmakāḥ karaṇāśrayatvāt karaṇa-grahaṇena gṛhyante | teṣāṃ kārya-karaṇānāṃ kartṛtvam utpādakatvaṃ yat tat kārya-karaṇa-kartṛtvaṃ tasmin kārya-karaṇa-kartṛtve hetuḥ kāraṇam ārambhakatvena prakṛtir ucyate | evaṃ kārya-karaṇa-kartṛtvena saṃsārasya kāraṇaṃ prakṛtiḥ |
kārya-kāraṇa-kartṛtve ity asminn api pāṭhe, kāryaṃ yat yasya pariṇāmas tat tasya kāryaṃ vikāro vikāri kāraṇaṃ tayor vikāra-vikāriṇoḥ kārya-kāraṇayoḥ kartṛtve iti | athavā, ṣoḍāśa vikārāḥ kāryaṃ sapta prakṛti-vikṛtayaḥ kāraṇaṃ tāny eva kārya-kāraṇāny ucyante teṣāṃ kartṛtve hetuḥ prakṛtir ucyate, ārambhakatvenaiva |
puruṣaś ca saṃsārasya kāraṇaṃ yathā syāt tad ucyate—puruṣo jīvaḥ kṣetrajño bhoktā iti paryāyaḥ, sukha-duḥkhānāṃ bhogyānāṃ bhoktṛtve upalabdhṛtve hetur ucyate | kathaṃ punar anena kārya-karaṇa-kartṛtvena sukha-duḥkha-bhoktṛtvena ca prakṛti-puruṣayoḥ saṃsāra-kāraṇatvam ucyate ? ity atrocyate—kārya-karaṇa-sukha-duḥkha-rūpeṇa hetu-phalātmanā prakṛteḥ pariṇāmābhāve, puruṣasya ca cetanasyāsati tad-upalabdhṛtve, kutaḥ saṃsāraḥ syāt ? yadā punaḥ kārya-karaṇa-sukha-duḥkha-svarūpeṇa hetu-phalātmanā pariṇatayā prakṛtyā bhogyayā puruṣasya tad-viparītasya bhoktṛtvenāvidyā-rūpaḥ saṃyogaḥ syāt, tadā saṃsāraḥ syād iti | ato yat prakṛti-puruṣayoḥ kārya-karaṇa-kartṛtvena sukha-duḥkha-bhoktṛtvena ca saṃsāra-kāraṇatvam uktam, tad yuktam | kaḥ punar ayaṃ saṃsāro nāma ? sukha-duḥkha-saṃbhogaḥ saṃsāraḥ | puruṣasya ca sukha-duḥkhānāṃ saṃbhoktṛtvaṃ saṃsāritvam iti

Rāmānuja

kāryaṃ śarīram; kāraṇāni jñānakarmātmakāni samanaskānīndriyāṇi / teṣāṃ kriyākāritve puruṣādhiṣṭhitā prakṛtir eva hetuḥ; puruṣādhiṣṭhitakṣetrākārapariṇataprakṛtyāśrayāḥ bhogasādhanabhūtāḥ kriyā ityarthaḥ / puruṣasyādhiṣṭhātṛtvam eva; tadapekṣayā, „kartā śāstrārthavattvāt” ityādikam uktam; śarīrādhiṣṭhānaprayatnahetutvam eva hi puruṣasya kartṛtvam / prakṛtisaṃsṛṣṭaḥ puruṣaḥ sukhaduḥkhānāṃ bhoktṛtve hetuḥ, sukhaduḥkhānubhavāśraya ityarthaḥ

Śrīdhara

vikārāṇāṃ prakṛti-sambhavatvaṃ darśayan puruṣasya saṃsāra-hetutvaṃ darśayati kāryeti | kāryaṃ śarīram | kāraṇāni sukha-duḥkha-sādhanānīndriyāṇi | teṣāṃ kartṛtve tad-ākāra-pariṇāme prakṛtir hetur ucyate kapilādibhiḥ | puruṣo jīvas tu tat-kṛta-sukha-duḥkhānāṃ bhoktṛtve hetur ucyate | ayaṃ bhāvaḥ yadyapi acetanāyāḥ prakṛteḥ svataḥ-kartṛtvaṃ na sambhavati tathā puruṣasyāpy avikāriṇo bhoktṛtvaṃ na sambhavati | tathāpi kartṛtvaṃ nāma kriyā-nirvartakatvam | tac cācetanasyāpi cetanādṛṣṭa-vaśāt caitanyādhiṣṭhitatvāt sambhavati yathā vahner ūrdhva-jvalanaṃ vayos tiryag gamanaṃ vatsādṛṣṭa-vaśāt gostanya-payasaḥ kṣaraṇam ity ādi | ataḥ puruṣa-sannidhānāt prakṛteḥ kartṛtvam ucyate bhoktṛtvaṃ ca sukha-duḥkha-saṃvedanaṃ, tac ca cetana-dharma eveti prakṛti-sannidhānāt puruṣasya bhoktṛtvam ucyate iti

Madhusūdana

vikārāṇāṃ prakṛti-sambhavattvaṃ vivecayan puruṣasya saṃsāra-hetutvaṃ darśayati kāryeti | kāryaṃ śarīraṃ karaṇānīndriyāṇi tat-sthāni trayodaśa dehārambhakāṇi bhūtāni viṣayāś ceha kārya-grahaṇena gṛhyante | guṇāś ca sukha-duḥkha-mohātmakāḥ karaṇāśrayatvāt karaṇa-grahaṇena gṛhyante | teṣāṃ kārya-karaṇānāṃ kartṛtve tad-ākāra-pariṇāme hetuḥ kāraṇam prakṛtir ucyate maharṣibhiḥ | kārya-karaṇeti dīrgha-pāṭhe ‚pi sa evārthaḥ | evaṃ prakṛteḥ saṃsāra-kāraṇatvaṃ vyākhyāya puruṣasyāpi yādṛśaṃ tat tad āha puruṣo kṣetrajñaḥ parā prakṛtir iti prāg vyākhyātaḥ | sa sukha-duḥkhānāṃ sukha-duḥkha-mohānāṃ bhogyānāṃ sarveṣām api bhoktṛtve vṛtty-uparaktopalambhe hetur ucyate

Viśvanātha

tasya māyā-saṃśleṣaṃ darśayati | kāryaṃ śarīram | kāraṇāni sukha-duḥkha-sādhanānīndriyāṇi | kartāra indriyādhiṣṭhātāro devās tatra tathādhyāsena puruṣa-saṃsargāt kāryādi-rūpeṇa pariṇatā syād avidyākhyayā sva-vṛttyā tad-adhyāsa-pradā ca syād ity arthaḥ | tat-kṛta-sukha-duḥkhānāṃ bhoktṛtve puruṣo jīva eva hetuḥ | ayaṃ bhāvaḥ yadyapi kāryatva-kāraṇatva-kartṛtva-bhoktṛtvāni prakṛti-dharmā eva syus tad api kāryatvādiṣu jaḍāṃśa-prādhānyāt, sukha-duḥkha-saṃvedana-rūpe bhoge tu caitanyāṃśa-prādhānyāt | prādhānyena vyapadeśā bhavantīti nyāyāt kāryatvādiṣu prakṛtir hetuḥ | bhoktṛtve puruṣo hetur ity ucyate iti

Baladeva

atha saṃsṛṣṭayos tayoḥ kārya-bhedam āha kāryeti śarīraṃ kāryaṃ jñāna-karma-sādhakatvād indriyāṇi kāraṇāni teṣāṃ kartṛtve tat-tad-ākāra-sva-pariṇāme prakṛtir hetuḥ | puruṣaḥ prakṛtistho hi ity agrimāt sva-saṃsargeṇa sacetanāṃ prakṛtiṃ puruṣo ‚dhitiṣṭhati | tad-adhiṣṭhitā tu sā tat-karmāṇu-guṇyena pariṇamamānā tat-tad-dehādīnāṃ sraṣṭrīti prakṛtyārpitānāṃ sukhādīnāṃ bhoktṛtve puruṣo hetus teṣāṃ bhoge sa eva kartey arthaḥ | prakṛty-adhiṣṭhātṛtvaṃ sukhādi-bhoktṛtvaṃ ca puruṣasya kāryam | tac ca śarīrādi-kartṛtvaṃ tu tad-adhiṣṭhātāyāḥ prakṛter iti puruṣasyaiva kartṛtvaṃ mukhyam | evam āha sūtrakāraḥ kartā śāstrārthavattvāt ity ādibhiḥ | pareśasya harer adhiṣṭhātṛtvaṃ tu sarvatrāvarjanīyam ity uktaṃ vakṣyate ca