B.G 17.23
ॐ तत् सदिति निर्देशो ब्रह्मणस्त्रिविधः स्मृतः। ब्राह्मणास्तेन वेदाश्च यज्ञाश्च विहिताः पुरा ॥२३॥
oṃ tat saditi nirdeśo brahmaṇastrividhaḥ smṛtaḥ। brāhmaṇāstena vedāśca yajñāśca vihitāḥ purā ॥23॥
[ॐ (oṃ) - Om; तत् (tat) - that; सत् (sat) - truth; इति (iti) - thus; निर्देशः (nirdeśaḥ) - indication; ब्रह्मणः (brahmaṇaḥ) - of Brahman; त्रिविधः (trividhaḥ) - threefold; स्मृतः (smṛtaḥ) - is remembered; ब्राह्मणाः (brāhmaṇāḥ) - the Brahmanas; तेन (tena) - by that; वेदाः (vedāḥ) - the Vedas; च (ca) - and; यज्ञाः (yajñāḥ) - sacrifices; च (ca) - and; विहिताः (vihitāḥ) - were ordained; पुरा (purā) - in ancient times;]
(Om, that, truth - thus is the threefold indication of Brahman remembered. By that, the Brahmanas, the Vedas, and sacrifices were ordained in ancient times.)
By the directive "Om, Tat, Sat", the three aspects of Brahman is remembered. By this, the Brahmanas, the Vedas, and sacrifices were instituted in ancient times.
Gīta Bhāshya 17.12
The directive "Om, Tat, Sat" is an ancient directive as indicated by the word 'purā'. 'Om' - shows the all-pervading nature of Brahmna; 'tat' - brings out the ever-changing, yet constant nature of Brahman; and 'sat' - highlights he is endowed with all auspicious qualities and also the reality of existence. The word 'tena', i.e. by him, implies 'by Brahman'. Thus, the Vedas and sacrifices were instituted in ancient times by Brahman for worship.
पुनश्च कर्मादीतिकर्तव्यताविधानार्थं अर्थवादमाह- ओं तत्सत् इत्यादिना॥
punaśca karmādītikartavyatāvidhānārthaṃ arthavādamāha- oṃ tatsat ityādinā॥
[पुनः (punaḥ) - again; च (ca) - and; कर्म (karma) - action; आदि (ādi) - beginning with; इति (iti) - thus; कर्तव्यता (kartavyatā) - duty; विधानार्थं (vidhānārthaṃ) - for the purpose of prescribing; अर्थवादम् (arthavādam) - eulogy; आह (āha) - says; ओं (oṃ) - Om; तत् (tat) - that; सत् (sat) - truth; इत्यादिना (ityādinā) - and so on;]
Again, for the purpose of prescribing actions and others as a duty, the eulogy says "Om tat sat" and so on.
परस्य ब्रह्मणो हि एतानि नामानि-
parasya brahmaṇo hi etāni nāmāni-
[परस्य (parasya) - of the Supreme; ब्रह्मणः (brahmaṇaḥ) - of Brahman; हि (hi) - indeed; एतानि (etāni) - these; नामानि (nāmāni) - names;]
These are indeed the names of the Supreme Brahman:
"ओतं जगद्यत्र स्वयं च पूर्णो वेदोक्तरूपोऽनुपचारतश्च। सर्वैः शुभैश्चाभियुतो न चान्यैः ओं तत्सदित्येनमतो वदन्ति॥"
"otaṃ jagadyatra svayaṃ ca pūrṇo vedoktarūpo'nupacārataśca। sarvaiḥ śubhaiścābhiyuto na cānyaiḥ oṃ tatsadityenamato vadanti॥"
[ओतं (otaṃ) - pervaded; जगत् (jagat) - Universe; यत्र (yatra) - where; स्वयं (svayam) - self; च (ca) - and; पूर्णः (pūrṇaḥ) - complete; वेद (veda) - Veda; उक्त (ukta) - stated; रूपः (rūpaḥ) - form; अनुपचारतः (anupacārataḥ) - without modification; च (ca) - and; सर्वैः (sarvaiḥ) - by all; शुभैः (śubhaiḥ) - auspicious; च (ca) - and; अभियुतः (abhiyutaḥ) - endowed; न (na) - not; च (ca) - and; अन्यैः (anyaiḥ) - by others; ओं (oṃ) - Om; तत् (tat) - that; सत् (sat) - truth; इति (iti) - thus; एनम् (enam) - him; अतः (ataḥ) - therefore; वदन्ति (vadanti) - they say;]
"The universe is pervaded by the self-complete form, 'Om', as stated in the Vedas, without modification, 'tat', endowed with all auspicious qualities 'sat', and not by others. Therefore, he is referred to as 'Om Tat Sat'."
इति हि ऋग्वेदखिलेषु।
iti hi ṛgvedakhileṣu।
[इति (iti) - thus; हि (hi) - indeed; ऋग्वेदखिलेषु (ṛgvedakhileṣu) - in the appendices of the Rigveda;]
- thus indeed, it is mentioned in the appendices of the Rigveda.
द्वितीयपादः तच्छब्दार्थः।
dvitīyapādaḥ tacchabdārthaḥ।
[द्वितीय (dvitīya) - second; पादः (pādaḥ) - portion of the verse; तत् (tat) - that; शब्द (śabda) - sound; अर्थः (arthaḥ) - meaning;]
The second part of the above verse refers to the meaning of 'tat', i.e. that, sound.
"सदेव सोम्य इदमग्र आसीत्"
"sadeva somya idamagra āsīt"
[सत् (sat) - existence; एव (eva) - indeed; सोम्य (somya) - dear; इदम् (idam) - this; अग्रे (agre) - in the beginning; आसीत् (āsīt) - was;]
"Indeed, dear, this was 'sat' i.e. existence, in the beginning."
इति च।
iti ca।
[इति (iti) - thus; च (ca) - and / as well;]
- stated thus as well
"ओमिति ब्रह्म"
"om iti brahma"
[ओम् (om) - Om; इति (iti) - thus; ब्रह्म (brahma) - Brahman;]
"'Om' is Brahman."
इति च।
iti ca।
[इति (iti) - thus; च (ca) - and / as well;]
- stated thus as well.
तेन ब्रह्मणा। आत्म पूजार्थम्। वेदविधिः र्व्यञ्जनम्। मा तु उक्ता पुरस्तात्॥
tena brahmaṇā। ātma pūjārtham। vedavidhiḥ rvyañjanam। mā tu uktā purastāt॥
[तेन (tena) - by him; ब्रह्मणा (brahmaṇā) - by Brahma; आत्म (ātma) - ātman; पूजार्थम् (pūjārtham) - for worship; वेदविधिः (vedavidhiḥ) - Vedic injunction; र्व्यञ्जनम् (rvyañjanam) - expression; मा (mā) - not; तु (tu) - but; उक्ता (uktā) - spoken; पुरस्तात् (purastāt) - before;]
(By him, by Brahma, for self-worship, the Vedic injunction is expressed, but not spoken before.)
The word 'tena', i.e. by him, implies Brahma. They are meant to worship the Ātman. The Vedic injunctions are an expression of that. The word 'purā', i.e. before, shows it is not spoken by the Lord now, but is an ancient knowledge.
