BhG 17.23

syntax

oṁ tat sat iti (OM, TAT, SAT)
brahmaṇaḥ (of Brahman) tri-vidhaḥ (threefold) nirdeśaḥ (designation) smṛtaḥ (known),
tena [tri-vidhena] (by this threefold) brāhmaṇāḥ ca (and brahmins) vedāḥ ca (and the Vedas) yajñāḥ ca (and sacrifices) purā (formerly) vihitāḥ [āsan] (they were made).

grammar

om tat sat	–	av. – OM, TAT, SAT (from: om – yes, sacred syllable OM, praṇava; tat – that, callingTAT; √as – to be, PPr sant – being, existing, true, the essence);
iti	–	av. – thus (used to close the quotation);
nirdeśaḥ	–	nirdeśa 1n.1 m. – instruction, description, designation (from: nir-√diś – to point out, to name);
brahmaṇaḥ	–	brahman 6n.1 n. – of the spirit, of the Veda (from: √bṛh – to increase);
tri-vidhaḥ	–	tri-vidha 1n.1 m. – threefold, of three parts (from: tri – three; vi-√dhā – to divide, vidhā – division, part);
smṛtaḥ	–	smṛta (√smṛ – to think, to remember) PP 1n.1 m. – known, remembered;
brāhmaṇāḥ	–	brāhmaṇa 1n.3 m. – brahmins (from: √bṛh – to increase, brahman – spirit, the Vedas);
tena	–	tat sn. 3n.1 m. – by that;
vedāḥ	–	veda 1n.3 m. – the Vedas (√vid – to know, to understand);
ca	–	av. – and;
yajñāḥ	–	yajña 1n.3 m. – sacrifices, worship (from: √yaj – to consecrate, to sacrifice, to worship);
ca	–	av. – and;
vihitāḥ	–	vihita (vi-√dhā – to put, to arrange) 1n.3 m. – placed, made;
purā	–	av. – formerly, anciently, in the beginning (from: √pur – to precede);

textual variants

nirdeśo → nirdiṣṭo (indicated);
brahmaṇas → brāhmaṇas ([designation] related to Brahman);
brāhmaṇās → brahmaṇā (by Brahman);

Śāṃkara

yajña-dāna-tapaḥ-prabhṛtīnāṃ sādguṇya-karaṇāyāyam upadeśa ucyate—
oṃ tat sad iti evaṃ nirdeśaḥ, nirdiśyate’neneti nirdeśaḥ | trividho nāma nirdeśo brahmaṇaḥ smṛtaś cintito vedānteṣu brahma-vidbhiḥ | brāhmaṇās tena nirdeśena trividhena vedāś ca yajñāś ca vihitāḥ nirmitāḥ purā pūrvam iti nirdeśa-stuty-artham ucyate

Rāmānuja

evaṃ vaidikānāṃ yajñatapodānānāṃ sattvādiguṇabhedena bheda uktaḥ; idānīṃ tasyaiva vaidikasya yajñādeḥ praṇavasaṃyogena tatsacchabdavyapadeśytayā ca lakṣaṇam ucyate
oṃ tat sad iti trividho ‚yaṃ nirdeśaḥ śabdaḥ brahmaṇaḥ smṛtaḥ brahmaṇo ‚nvayī bhavati / brahma ca vedaḥ / vedaśabdena vaidikaṃ karmocyate / vaidikaṃ yajñādikam / yajñādikaṃ karma oṃ tat sad iti śabdānvitaṃ bhavati / om iti śabdasyānvayo vaidikakarmāṅgatvena prayogādau prayujyamānatayā; tat sad iti śabdayor anvayaḥ pūjyatvāya vācakatayā / tena trividhena śabdenānvitā brāhmaṇāḥ vedānvayinas traivarṇikāḥ vedāś ca yajñāś ca purā vihitāḥ purā mayaiva nirmitā ityarthaḥ

Śrīdhara

nanv evaṃ vicāryamāṇe sarvam api yajña-tapo-dānādi rājasa-tāmasa-prāyam eveti vyartho yajñādi-prayāsa ity āśaṅkya tathāvidhasyāpi sāttvikatvopapādanāt prakāraṃ darśayitum āha om iti | oṃ tat sad iti trividho brahmaṇaḥ paramātmano nirdeśo nāma-vyapadeśaḥ smṛtaḥ śiṣṭaiḥ | tatra tāvad om iti brahma ity ādi śruti-prasiddher om iti brahmaṇo nāma | jagat-kāraṇatvenāti-prasiddhatvād aviduṣāṃ parokṣatvāc ca tac-chabdo ‚pi brahmaṇo nāma | paramārtha-sattva-sādhutva-praśastatvādibhiḥ sac-chabdo ‚pi brahmaṇo nāma | sad eva saumyedam agra āsīt ity ādi śruteḥ | ayaṃ trividho ‚pi nāma nirdeśena brāhmaṇāś ca vedāś ca yajñāś purā sṛṣṭy-ādau vihitā vidhātrā nirmitāḥ | saguṇī-kṛtā iti vā | yathā yasyāyaṃ trividho nirdeśas tena paramātmanā brāhmaṇādayaḥ pavitratamāḥ sṛṣṭāḥ | tasmāt tasyāyaṃ trividho nirdeśo ‚tipraśasta ity arthaḥ

Madhusūdana

tad evam āhāra-yajña-tapo-dānānāṃ traividhya-kathanena sāttvikāni tāny ādeyāni rājasa-tāmasāni tu parihartavyānīty uktam | tatrāhārasya dṛṣṭārthatvena nāsty aṅga-vaiguṇyena phalābhāva-śaṅkā | yajña-tapo-dānānāṃ tv adṛṣṭārthānām aṅga-vaiguṇyād apūrvānutpattau phalābhāvaḥ syād iti sāttvikānī̀am api teṣām ānarthakyaṃ prāptaṃ pramāda-bahulatvād anuṣṭhātṝṇām atas tad-vaiguṇya-parihārārya oṃ tat sad iti bhagavan-nāmoccāraṇa-rūpaṃ sāmānya-prāyaścittaṃ parama-kāruṇikatayopadiśati bhagavān om iti | oṃ tat sad ity evaṃ-rūpo brahmaṇaḥ paramātmano nirdeśo nirdiśyate ‚neneti nirdeśaḥ pratipādaka-śabdo nāmeti yāvat | trividhas tisro vidhā avayavā yasya sa trividhaḥ smṛto vedānta-vidbhiḥ | eka-vacanāt try-avayavam ekaṃ nāma praṇavavat | yasmāt pūrvair maharṣibhir ayaṃ brahmaṇo nirdeśaḥ smṛtas tasmād idānīntanair api smartavya iti vidhir atra kalpyate | vaṣaṭ-kartuḥ prathama-bhakṣa ity ādiṣv iva vacanāni tv apūrvatvād iti nyāyāt | yajña-dāna-tapaḥ-kriyā-saṃyogāc cāsya tad avaiguṇyam eva phalaṃ ##ṣṭāśva-dagdha-ratha-vat-parasparākāṅkṣayā kalpyate |
pramādāt kurvatāṃ karma pracyavetādhvareṣu yat |
smaraṇād eva tad viṣṇoḥ sampūrṇaṃ syād iti śrutiḥ ||
iti smṛtes tathaiva śiṣṭācārāc ca | brahmaṇo nirdeśaḥ stūyate karma-vaiguṇya-parihāra-sāmarthya-kathanāya | brāhmaṇā iti traivarṇikopalakṣaṇam | brāhmaṇādyāḥ kartāro vedāḥ karaṇāni yajñāḥ karmāṇi tena brahmaṇo nirdeśena karaṇa-bhūtena purā vihitāḥ prajāpatinā | tasmād yajñādi-sṛṣṭi-hetutvena tad-vaiguṇya-parihāra-samartho mahā-prabhāvo ‚yaṃ nirdeśa ity arthaḥ

Viśvanātha

commentary under the verse BhG 17.24

Baladeva

tad evaṃ tapo-yajña-tapo-dānānāṃ traividhya-kathanena sāttvikānāṃ teṣām upadeyatvaṃ, rājasādīnāṃ heyatvaṃ ca darśitam | atha sāttvikādhikāriṇāṃ yajñādīni viṣṇu-nāma-pūrvakāṇy evabhavantīty ucyate om iti | om ity ādikas trividho brahmaṇo viṣṇor nirdeśo nāma-dheyaṃ śiṣṭaiḥ smṛtaḥ | om ity etad brahmaṇo nediṣṭaṃ nāma iti śruteḥ | om ity ekaṃ nāma | tat tvam asi iti śruteḥ tad iti dvitīyaṃ nāma | sad eva saumya iti śruteḥ sad iti tṛtīyaṃ nāma | upalakṣaṇam idam | viṣṇv-ādi-nāmnāṃ tena trividhena nirdeśena brāhmaṇā vedā yajñāś ca purā caturmukhena vihitāḥ prakaṭitās tasmān mahā-prabhāvo ‚yaṃ nirdeśas tat-pūrvakāṇāṃ yajñādīnāṃ nāṅga-vaiguṇyam | tena phala-vaiguṇyaṃ ca neti