BhG 4.39

syntax

tat-paraḥ (devoted to that) saṁyatendriyaḥ (who put the senses under control) śraddhā-vān (having faith) jñānam (knowledge) labhate (he obtains),
jñānam (knowledge) labdhvā (after obtaining)
acireṇa (speedily) parām (the supreme) śāntim (tranquility) adhigacchati (he obtains).

grammar

śraddhā-vān	–	śraddhā-vant 1n.1 m. – who has faith (from: śrat- – in compounds: faith; √dhā – to put [faith]; śraddhā – faith, confidence; -mant / -vant – suffix denoting one who possesses);
labhate	–	√labh (to obtain, to gain) Praes. Ā 1v.1 – he obtains;
jñānam	–	jñāna 2n.1 n. – knowledge, wisdom (from: √jñā – to know, to understand);
tat-paraḥ	–	tat-para 1n.1 m. – yasya tat param asti saḥ – one for whom the supreme [object] is that (from: tat – sn. that; para – beyond, ancient, final, the best, the supreme; suffix: para – devoted, engaged in; tat-para – devoted to that);
saṁyatendriyaḥ	–	saṁyata-indriya 1n.1 m.; BV: yasyendriyāṇi saṁyatāni santi saḥ – whose senses are controlled (from: sam-√yam – to hold together, to restrain, PP saṁyata – restrained, controlled; √ind – to be powerful, indriya – the senses);
jñānam	–	jñāna 2n.1 n. – knowledge, wisdom (from: √jñā – to know, to understand);
labdhvā	–	√labh (to obtain, to gain) absol. – after obtaining;
parām	–	para 2n.1 f. – distant, final, the best, the supreme;
śāntim	–	śānti 2n.1 f. – tranquility, peace, satisfaction, end, death (from: √śam – to calm, to put to an end, to destroy);
a-cireṇa	–	av. – speedily, not for long (from: cira – long, delay);
adhigacchati	–	adhi-√gam (to cross over, to obtain) Praes. P 1v.1 – he obtains;

textual variants

tat-paraḥ saṁyatendriyaḥ → mat-paraḥ saṁjiteṁdriyaḥ (devoted to me, who conquered the senses);
parāṁ → praraṁ (next);

Śāṃkara

yenaikāntena jñāna-prāptir bhavati sa upāya upadiśyate —-

śraddhāvān śraddhālur labhate jñānam | śraddhālutve’pi bhavati kaścin manda-prasthānaḥ, ata āha —- tat-paraḥ | gurūpāsadanādāv abhiyukto jñāna-labdhy-upāye śraddhāvān | tat-paro’py ajitendriyaḥ syāt ity ata āha —- saṃyatendriyaḥ | saṃyatāni viṣayebhyo nivartitāni yasyendriyāṇi sa saṃyatendriyaḥ | ya evaṃbhūtaḥ śraddhāvān tat-paraḥ saṃyatendriyaś ca so’vaśyaṃ jñānaṃ labhate | praṇipātādis tu bāhyo’naikāntiko’pi bhavati, māyāvitvādi-saṃbhavāt | na tu tat śraddhāvattvādau ity ekāntato jñāna-labdhy-upāyaḥ | kiṃ punar jñāna-lābhāt syād ity ucyate —jñānaṃ labdhvā paraṃ mokṣākhyāṃ śāntim uparatim acireṇa kṣipram evādhigacchati | samyag-darśanāt kṣipram eva mokṣo bhavatīti sarva-śāstra-nyāya-prasiddhaḥ suniścito’rthaḥ

Rāmānuja

tad eva vispaṣṭam āha

evam upadeśāj jñānaṃ labdhvā copadiṣṭajñānavṛddhau śraddhāvān tatparaḥ tatraiva niyatamanāḥ taditaraviṣayāt saṃyatendriyo ‚cireṇa kālenoktalakṣaṇavipākadaśāpannaṃ jñānaṃ labhate, tathāvidhaṃ jñānaṃ labdhvā parām śāntim acireṇādhigacchati paraṃ nirvāṇam āpnoti

Śrīdhara

kiṃ ca śraddhāvān iti | śraddhāvān gurūpadiṣṭe ‚rthe āstikya-buddhimān | tat-paras tad-eka-niṣṭhaḥ | saṃyatendriyaś ca | taj jñānaṃ labhate | nānyaḥ | ataḥ śraddhādi-sampattyā jñāna-lābhāt prāk karma-yoga eva śuddhy-artham anuṣṭheyaḥ | jñāna-lābhānantaraṃ tu na tasya kiṃcit kartavyam ity āha jñānaṃ labdhvā tu mokṣam acireṇa prāpnoti

Madhusūdana

yenaikāntena jñāna-prāptir bhavati sa upāyaḥ pūrvokta-praṇipātādy-apekṣayāpy āsannatara ucyate śraddhāvān iti | guru-vedānta-vākyeṣv idam ittham veti pramā-rūpāstikya-buddhiḥ śraddhā tadvān puruṣo labhate jñānam | etādṛśo ‚pi kaścid alasaḥ syāt tatrāha tat-paraḥ | gurūpāsanādau jñānopāye ‚tyantābhiyuktaḥ | śraddhāvāṃs tat-paro ‚pi kaścid ajitendriyaḥ syād ata āha saṃyatendriyaḥ | saṃyatāni viṣayebhyo nivartitānīndriyāṇi yena sa saṃyatendriyaḥ | ya evaṃ viśeṣaṇa-traya-yuktaḥ so ‚vaśyaṃ jñānaṃ labhate | praṇipātādis tu bāhyo māyāvitvādi-sambhavād anaikāntiko ‚pi | śraddhāvattvādis tv aikāntika upāya ity arthaḥ|

īdṛśenopāyena jñānaṃ labdhvā parāṃ caramāṃ śāntim avidyā-tat-kārya-nivṛtti-rūpāṃ muktim acireṇa tad-avyavadhānenaivādhigacchati labhate | yathā hi dīpaḥ svotpatti-mātreṇaivāndhakāra-nivṛttiṃ karoti na tu kaṃcit sahakāriṇam apekṣate tathā jñānam api svotpatti-mātreṇaivājñāna-nivṛttiṃ karoti na tu kiṃcit prasaṅkhyānādikam apekṣata iti bhāvaḥ

Viśvanātha

tarhi kīdṛśaḥ san kadā prāpnotīty ata āha śraddhāvān iti | śraddhā niṣkāma-karmaṇaivāntaḥkaraṇa-śuddhyaiva jñānaṃ syād iti śāstrārthaṃ āstikya-buddhis tadvān eva | tat-paras tad-anuṣṭhāna-niṣṭhas tādṛśo ‚pi yadā saṃyatendriyaḥ syāt tadā parāṃ śāntim saṃsāra-nāśam

Baladeva

kīdṛśaḥ san kadā vindatīty āha śraddhāvān iti | niṣkāmena karmaṇā hṛd-viśuddhau jñānaṃ syād iti | dṛḍha-viśvāsaḥ śraddhā tadvān | tat-paras tad-anuṣṭhāna-niṣṭhas tādṛg api yadā saṃyatendriyas tadā parāṃ śāntim muktim