BhG 15.17

syntax

yaḥ īśvaraḥ (that lord which) avyayaḥ ca (and unchangeable) loka-trayam (three worlds) āviśya (after entering) bibharti (he sustains),
[saḥ] tu (but he) [kṣara-puruṣākṣara-puruṣābhyām] anyaḥ (other than perishable and imperishable man) uttamaḥ puruṣaḥ (the supreme person) paramātmā iti (the supreme self) udāhṛtaḥ (he is declared).

grammar

uttamaḥ	–	uttama 1n.1 m. – the best, uppermost, highest (superlative of: ud – upwards, above);
puruṣaḥ	–	puruṣa 1n.1 m. – a person (from: √pur – to precede, to lead or √pṝ – to fill, to nourish, puru – abundance, pūru – people);
tu	–	av. – but, then, or, and;
anyaḥ	–	anya sn. 1n.1 m. – other;
paramātmā	–	parama-ātman 1n.1 m. – the supreme self (from: para – beyond, ancient, final, the best, the supreme, parama –  supreme, the highest; ātman – self; or param ātman – the ancient self;
iti	–	av. – thus (used to close the quotation);
udāhṛtaḥ	–	ud-ā-hṛta (ud-ā-√hṛ – to set up, to declare), PP 1n.1 n. – set up, declared;
yaḥ	–	yat sn. 1n.1 m. – he who;
loka-trayam	–	loka-traya 2n.1 n.; lokānāṁ trayam iti – three worlds (from: loka – world; tri – three; traya – threefold);
āviśya	–	ā-√viś (to approach, to enter) absol. – after entering, after approaching;
bibharti	–	√bhṛ (to bear, to carry, to hold) Praes. P 1v.1 – he sustains;
avyayaḥ	–	a-vyaya 1n.1 m. – unchangeable (from: vi-√i – to go away, to disappear, vyaya – going away, changeable, expense);
īśvaraḥ	–	īśvara 1n.1 m. – ruler, lord (from: √xīś – to own, to reign, īśa – ruler, lord);

textual variants

avyaya → avyayam (unchangeable [three worlds]);

Śāṃkara

ābhyāṃ kṣarākṣarābhyām anyo vilakṣaṇaḥ kṣarākṣaropādhi-dvaya-doṣeṇāspṛṣṭaḥ nitya-śuddha-buddham ukta-svabhāvaḥ—
uttama utkṛṣṭatamaḥ puruṣas tv anyo’tyanta-vilakṣaṇa ābhyāṃ paramātmeti paramaś cāsau dehādy-avidyā-kṛtātmabhyaḥ, ātmaś ca sarva-bhūtānāṃ pratyak-cetanaḥ, ity ataḥ paramātmety udāhṛta ukto vedānteṣu | sa eva viśiṣyate yo loka-trayaṃ bhūr-bhuvaḥ-svar-ākhyaṃ svakīyayā caitanya-bala-śaktyā āviśya praviśya bibharti svarūpa-sad-bhāva-mātreṇa bibharti dhārayati | avyayo nāsya vyayo vidyata ity avyayaḥ | kaḥ ? īśvaraḥ sarvajño nārāyaṇākhya īśana-śīlaḥ

Rāmānuja

uttamaḥ puruṣas tu tābhyāṃ kṣarākṣaraśabdanirdiṣṭābhyāṃ baddhamuktapuruṣābhyām anyaḥ arthāntarabhūtaḥ paramātmety udāhṛtaḥ sarvāsu śrutiṣu / paramātmeti nirdeśād eva hy uttamaḥ puruṣo baddhamuktapuruṣābhyāṃ arthāntarabhūta ity avagamyate / katham? yo lokatrayam āviśya bibharti / lokyata iti lokaḥ; tattrayaṃ lokatrayam / acetanaṃ tatsaṃsṛṣṭaś cetano muktaś ceti pramāṇāvagamyam etat trayaṃ ya ātmatayā āviśya bibharti, sa tasmād vyāpyād bhartavyāc cārthāntarabhūtaḥ / itaś coktāl lokatrayād arthāntarabhūtaḥ; yataḥ so ‚vyayaḥ, īśvaraś ca; avyayasvabhāvo hi vyayasvabhāvād acetanāt tatsaṃbandhena tadanusāriṇaś ca cetanād acitsaṃbandhayogyatayā pūrvasaṃbandhino muktāc cārthāntarabhūta eva / tathaitasya lokatrayasyeśvaraḥ, īśitavyāt tasmād arthāntarabhūtaḥ

Śrīdhara

yad artham etau lakṣitau tam āha uttama iti | etābhyāṃ kṣarāksarābhyām anyo vilakṣaṇas tu uttamaḥ puruṣaḥ | vailakṣaṇyam evāha paramaś cāsāv ātmā cety udāhṛtaḥ uktaḥ śrutibhiḥ | ātmatvena kṣarād acetanād vilakṣaṇaḥ | paramatvenākṣarāc cetanād bhoktur vilakṣaṇa ity arthaḥ | paramātmatvaṃ darśayati yo loka-trayam iti | ya īśvara īśana-śīlo ‚vyayaś ca nirvikāra eva san loka-trayaṃ kṛsnam āviśya bibharti pālayati

Madhusūdana

ābhyāṃ kṣarākṣarābhyāṃ vilakṣaṇaḥ kṣarākṣaropādhi-dvaya-doṣeṇāspṛṣṭo nitya-śuddha-buddha-mukta-svabhāvaḥ uttama iti | uttama utkṛṣṭatamaḥ puruṣas tv anyonya evātyanta-vilakṣaṇa ābhyāṃ kṣarākṣarābhyāṃ jaḍa-rāśibhyām ubhaya-bhāsakas tṛtīyaś cetana-rāśir ity arthaḥ | paramātmety udāhṛto ‚nna-maya-prāṇa-maya-mano-maya-jñāna-mayānanda-mayebhyaḥ pañcabhyo ‚vidyā-kalpitātmabhyaḥ paramaḥ prakṛṣṭo ‚kalpito brahma pucchaṃ pratiṣṭhety ukta ātmā ca sarva-bhūtānāṃ pratyak-cetana ity ataḥ paramātmety uktao vedānteṣu | yaḥ paramātmā loka-trayam bhūr-bhuvaḥ-svar-ākhyaṃ sarvaṃ jagad iti yāvat | āviśya svakīyayā māyā-śaktyādhiṣṭhāya bibharti sattā-sphūrti-pradānena dhārayati poṣayati ca | kīdṛśaḥ ? avyayaḥ sarva-vikāra-śūnya īśvaraḥ sarvasya niyantā nārāyaṇaḥ sa uttamaḥ puruṣaḥ paramātmety udāhṛta ity anvayaḥ | sa uttamaḥ puruṣa iti śruteḥ

Viśvanātha

jñānibhir upāsyaṃ brahmoktvā yogibhir upāsyaṃ paramātmānam āha uttama iti | tu-śabdaḥ pūrva-vaiśiṣṭhyād dyotakaḥ | jñānibhyaś cādhiko yogīty upāsaka-vaiśiṣṭyād evopāsya-vaiśiṣṭyaṃ ca labhyate | paramātma-tattvam eva darśayati ya īśvara īsana-śīlo ‚vyayo nirvikāra eva san loka-trayaṃ kṛtsnam āviśya bibharti dhārayati pālayati ca

Baladeva

yad arthaṃ dvau puruṣau nirūpitau tam āha uttama iti | anyaḥ kṣarākṣarābhyāṃ na tu tayor evaikaḥ saṅkalpa iti bhāvaḥ | tatra śruti-sammatim āha paramātmeti | uttamatā-prayojakaṃ dharmam āha yo loketi | na caitaj jagad-vidhāraṇa-pālana-rūpam īśanaṃ baddhasya jīvasya karmāsambhavāt | na ca muktasya jagad-vyāpāra-varjam iti pratiṣedhāc ca