17.23

ॐतत्सदिति निर्देशो ब्रह्मणस्त्रिविधः स्मृतः ।
ब्राह्मणास्तेन वेदाश्च यज्ञाश्च विहिताः पुरा ॥

oṃ tat sad iti nirdeśo brahmaṇas trividhaḥ smṛtaḥ
brāhmaṇās tena vedāś ca yajñāś ca vihitāḥ purā

śrībhagavān (श्रीभगवान्) is still speaking. The sorting pauses, and three words are named.

The verse

ॐ तत् सत् is remembered as the threefold pointer to ब्रह्मन्, and by it the brāhmaṇas (ब्राह्मण), the Vedas (वेद), and the sacrifices were ordained of old.

नेपालीमा

ॐ तत् सत्लाई ब्रह्मन्तिर देखाउने तीन किसिमको निर्देश भनी सम्झिन्छन्, र त्यसैद्वारा ब्राह्मण, वेद र यज्ञ प्राचीन कालमा स्थापित भए।

Where it sits

Sacrifice, austerity, and gift have each been three. He now gives the three words those acts are said under. The rest of the chapter says how oṃ (ॐ), how tat (तत्), and how sat (सत्) are used, and then what an act is when faith is missing.

Split: ॐ + तत् + सत् + इति + निर्देशः + ब्रह्मणः + त्रि-विधः + स्मृतः + ब्राह्मणाः + तेन + वेदाः + च + यज्ञाः + च + विहिताः + पुरा

oṃ + tat + sat + iti + nirdeśaḥ + brahmaṇaḥ + tri-vidhaḥ + smṛtaḥ + brāhmaṇāḥ + tena + vedāḥ + ca + yajñāḥ + ca + vihitāḥ + purā

Sanskrit, in depth

The words

देवनागरी	Word	Grammar	Sense
ॐ	oṃ	indeclinable	oṃ (ॐ). The syllable, named as itself.
तत्	tat	indeclinable	tat (तत्), "that," named as a word.
सत्	sat	indeclinable	sat (सत्), "being, the real," named as a word.
इति	iti	indeclinable	thus. It closes the three words.
निर्देशः	nirdeśaḥ	nominative singular	a pointer, a designation. nir (निर्) with deśa (देश) "pointing out."
ब्रह्मणः	brahmaṇaḥ	genitive singular	of brahman (ब्रह्मन्).
त्रि-विधः	tri-vidhaḥ	nominative singular	threefold. Agrees with nirdeśaḥ (निर्देशः).
स्मृतः	smṛtaḥ	nominative singular	remembered. Agrees with nirdeśaḥ (निर्देशः).
ब्राह्मणाः	brāhmaṇāḥ	nominative plural	the brāhmaṇa (ब्राह्मण) people.
तेन	tena	instrumental singular	by that. By the triple pointer.
वेदाः	vedāḥ	nominative plural	the veda (वेद).
च	ca	indeclinable	and.
यज्ञाः	yajñāḥ	nominative plural	the sacrifices.
च	ca	indeclinable	and.
विहिताः	vihitāḥ	nominative plural	ordained, laid down. Agrees with the three nominative plurals.
पुरा	purā	indeclinable	of old.

The phrases

ॐ तत् सत् इति निर्देशः ब्रह्मणः त्रिविधः स्मृतः oṃ tat sat iti nirdeśaḥ brahmaṇaḥ trividhaḥ smṛtaḥ names the three and says what they are. oṃ (ॐ), tat (तत्), sat (सत्): this is remembered as the threefold pointer to brahman (ब्रह्मन्). nirdeśaḥ (निर्देशः) is the noun. trividhaḥ (त्रिविधः) and smṛtaḥ (स्मृतः) agree with it. brahmaṇaḥ (ब्रह्मणः) is genitive, "of brahman (ब्रह्मन्)."

brāhmaṇāḥ tena vedāḥ ca yajñāḥ ca vihitāḥ purā (ब्राह्मणाः तेन वेदाः च यज्ञाः च विहिताः पुरा) is what was laid down by that pointer. The brāhmaṇas (ब्राह्मण), the Vedas (वेद), and the sacrifices were ordained by it, of old. One verb-adjective, vihitāḥ (विहिताः), for the three subjects. tena (तेन) is the instrument.

Sanskrit in this line

सत् + इति sat + iti is recited sad iti (सदिति). Final t (त्) before a vowel is written d (द्). The word in the split is still sat (सत्). oṃ tat sad iti (ॐतत्सदिति) is four words, not one name. brahmaṇaḥ (ब्रह्मणः) is genitive, "of." The instrumental "by brahman (ब्रह्मन्)" would be brahmaṇā (ब्रह्मणा).

Say it back

The three words, then the pointer, then what was ordained by it. If oṃ tat sat (ॐ तत् सत्) is said as the three strands, stay here. The strands are already finished. These are the pointer to brahman (ब्रह्मन्).