BhG 4.3

syntax

[tvam] (you) me (my) bhaktaḥ (devotee) sakhā ca (and friend) asi iti (you are).
ayam saḥ eva (that indeed) purātanaḥ (ancient) yogaḥ (yoga) adya (today) mayā (by me) te (to you) proktaḥ (spoken).
etat hi (this indeed) uttamam (the greatest) rahasyam (secret) [asti] (it is).

grammar

saḥ	–	tat sn. 1n.1 m. – that;
eva	–	av. – certainly, just, merely;
ayam	–	idam sn. 1n.1 m. – this;
mayā	–	asmat sn. 3n.1 – by me;
te	–	yuṣmat sn. 4n.1 – to you (shortened form of: tubhyam);
a-dya	–	av. – today, now (from: √div – to shine, dyu – day, heaven);
yogaḥ	–	yoga 1n.1 m. – yoga, yoking, application, a means, one of the schools of Hindu philosophy (from:√yuj – to yoke, to join, to engage);
proktaḥ	–	prokta (pra-√vac – to declare, to speak) PP 1n.1 m. – spoken;
purātanaḥ	–	purā-tana 1n.1 m. – belonging to the past, ancient (from: √pur – to precede, av. purā – formerly)
bhaktaḥ	–	bhakta (√bhaj – to share, to love, to rejoice, to worship) PP 1n.1 m. – distributed, divided, loved; worshipper, devotee, loving;
asi	–	√as (to be) Praes. P 2v.1 – you are;
me	–	asmat sn. 6n.1 – my (shortened form of: mama);
sakhā	–	sakhi 1n.1 m. – friend, companion (from: √sac – to be associated or united with);
ca	–	av. – and;
iti	–	av. – thus (used to close the quotation);
rahasyam	–	rahasya 1n.1 n. – a secret (from: √rah – to separate, to leave, rahas – loneliness, secret);
hi	–	av. – because, just, indeed, surely;
etat	–	etat sn. 1n.1 n. – this;
uttamam	–	uttama 1n.1 n. – uppermost, highest, most elevated (superlative of: ud – upwards, above);

textual variants

sa evāyaṁ → sa eva ca (and he indeed);
purātanaḥ → sanātanaḥ (ancient);
ceti → cāsi (and you are);
rahasyaṁ hy etad → rahasyaṁ caitad / rahasyam etad / rahasyaṁ hy etam (and this secret / this secret / indeed this secret);

Śāṃkara

durlabhān ajitendriyān prāpya naṣṭaṃ yogam imam upalabhya lokaṃ cāpuruṣārtha-sambandhinaṃ—

sa evāyaṃ mayā te tubhyam adya idānīṃ yogaḥ proktaḥ purātanaḥ | bhakto’si me sakhā cāsīti | rahasyaṃ hi yasmād etad uttamaṃ yogo jñānam ity arthaḥ

Rāmānuja

tṛtīye ‚dhyāye prakṛtisaṃsṛṣṭasya mumukṣoḥ sahasā jñānayoge ‚nadhikārāt karmayoga eva kāryaḥ, jñānayogādhikāriṇo ‚py akartṛtvānusandhānapūrvakakarmayoga eva śreyān iti sahetukam uktam; śiṣṭatayā vyapadeśyasya tu viśeṣataḥ karmayoga eva kārya iti coktam / caturthenedānīm asyaiva karmayogasya nikhilajagaduddharaṇāya manvantarādāv evopadiṣṭatayā kartavyatāṃ draḍhayitvā antargatajñānatayāsyaiva jñānayogākaratāṃ pradarśya, karmayogasvarūpam, tadbhedāḥ, karmayoge jñānāṃśasyaiva prādhānyaṃ cocyate / prasaṅgāc ca bhagavadavatārayāthātmyam ucyate /

yo ‚yaṃ tavodito yogaḥ sa kevalaṃ yuddhaprotsāhanāyedānīm udita iti na mantavyam / manvantarādāv eva nikhilajagaduddharaṇāya paramapuruṣārthalakṣaṇamokṣasādhanatayā imaṃ yogam aham eva vivasvate proktavān, vivasvāṃś ca manave, manur ikṣvakave / ity evaṃ saṃpradāyaparamparayā prāptam imaṃ yogaṃ pūrve rājarṣayo ‚viduḥ / sa mahatā kālena tattacchrotṛbuddhimāndyād vinaṣṭaprāyo ‚bhūt / sa evāyam askhalitasvarūpaḥ purātano yogaḥ sakhyenātimātrabhaktyā ca mām eva prapannāya te mayā proktaḥ saparikaras savistaram ukta ityarthaḥ / madanyena kenāpi jñātuṃ vaktuṃ cāśakyam, yata idaṃ vedāntoditam uttamaṃ rahasyaṃ jñānam

Śrīdhara

sa evāyam iti | sa evāyaṃ yogo ‚dya vicchinne sampradāye sati punaś ca te tubhyam uktaḥ | yatas tvaṃ mama bhakto ‚si sakhā ca | anyasmai mayā nocyate | hi yasmād etad uttamaṃ rahasyam

Madhusūdana

ya evaṃ pūrvam upadiṣṭo ‚py adhikārya-bhāvād vicchinna-sampradāyo ‚bhūt | yaṃ vinā ca puruṣārtho na labhyate | sa evāyaṃ purātano ‚nādi-guru-paramparā-gato yogo ‚dya sampradāya-viccheda-kāle mayātisnigdhena te tubhyaṃ prakarṣeṇoktaḥ | na tv anyasmai kasmaicit | kasmāt ? bhakto ‚si me sakhā ceti | iti-śabdo hetau | yasmāt tvaṃ mama bhaktaḥ śaraṇāgatatve saty atyanta-prītimān sakhā ca samāna-vayāḥ snigdha-sahāyo ‚si sarvadā bhavasi atas tubhyam ukta ity arthaḥ anyasmai kuto nocyate tatrāha | hi yasmād etaj jñānam uttamaṃ rahasyam atigopyam

Viśvanātha

tvāṃ praty evāsya proktatve hetuḥ : bhakto dāsaḥ sakhā ceti bhāva-dvayam | anyas tu arvācīnaṃ praty eva avaktavyatve hetū rahasyam iti

Baladeva

sa eva tadānupūrvika-vacana-vācyo yogo mayā tvat-sakhenātisnigdhena te tubhyaṃ mat-sakhāyeti snigdhāya proktas tvaṃ me bhaktaḥ prapannaḥ sakhā cāsīti hetor na tv anyasmai kasmaicit | tatra hetuḥ rahasyam iti | hi yasmād uttamaṃ rahasyam iti gopyam etat