4.34

तद्विद्धि प्रणिपातेन परिप्रश्नेन सेवया ।
उपदेक्ष्यन्ति ते ज्ञानं ज्ञानिनस्तत्त्वदर्शिनः ॥

tad viddhi praṇipātena paripraśnena sevayā
upadekṣyanti te jñānaṃ jñāninastattvadarśinaḥ

Kṛṣṇa (कृष्ण) is still speaking, to Arjuna.

The verse

Know that by prostration, by question, and by service; the knowers who see the truth will teach you the knowledge.

नेपालीमा

त्यो ज्ञान प्रणाम, प्रश्न र सेवाले बुझ। सत्य देख्ने ज्ञानीहरूले तिमीलाई ज्ञान सिकाउनेछन्।

Where it sits

4.33 set knowledge above the other sacrifices, and this verse says it is learned, not taken by private force, from people who already see, by three instruments. What that knowledge does to confusion and to old action occupies the rest of the chapter.

Split: तत् + विद्धि + प्रणिपातेन + परिप्रश्नेन + सेवया + उपदेक्ष्यन्ति + ते + ज्ञानम् + ज्ञानिनः + तत्त्व-दर्शिनः

tat + viddhi + praṇipātena + paripraśnena + sevayā + upadekṣyanti + te + jñānam + jñāninaḥ + tattva-darśinaḥ

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
तत्tataccusativethat. The knowledge of 4.33.
विद्धिviddhiimperative, 2nd singularknow.
प्रणिपातेनpraṇipātenainstrumental singularby prostration, by falling forward at the feet.
परिप्रश्नेनparipraśnenainstrumental singularby question. paripraśna (परिप्रश्न) is asking all the way around a thing.
सेवयाsevayāinstrumental singularby service.
उपदेक्ष्यन्तिupadekṣyantifuture, 3rd pluralthey will teach. From upa-diś (उप-दिश्).
तेtedative encliticto you.
ज्ञानम्jñānamaccusativeknowledge.
ज्ञानिनःjñāninaḥnominative pluralthe knowers. Subject of upadekṣyanti (उपदेक्ष्यन्ति).
तत्त्व-दर्शिनःtattva-darśinaḥnominative pluralthe seers of truth. tattva (तत्त्व) is "that-ness," what is so. Agrees with jñāninaḥ (ज्ञानिनः).

The phrases

tat viddhi praṇipātena paripraśnena sevayā (तत् विद्धि प्रणिपातेन परिप्रश्नेन सेवया) is how to come to the knowledge. Know that by prostration, by question, and by service. tat viddhi (तत् विद्धि) is tad viddhi (तद्विद्धि): t (त्) before v (व्) becomes d (द्). Three instrumentals, one command.

upadekṣyanti te jñānaṃ jñāninaḥ tattvadarśinaḥ (उपदेक्ष्यन्ति ते ज्ञानं ज्ञानिनः तत्त्वदर्शिनः) is who does the teaching. The knowers, those who see the truth, will teach the knowledge to you. jñāninaḥ tattvadarśinaḥ (ज्ञानिनः तत्त्वदर्शिनः) is jñāninastattvadarśinaḥ (ज्ञानिनस्तत्त्वदर्शिनः): aḥ (अः) before voiceless t (त्) becomes as (अस्). te (ते) is dative, "to you," not a second subject. The subject is already jñāninaḥ (ज्ञानिनः).

Sanskrit in this line

praṇipātena (प्रणिपातेन), paripraśnena (परिप्रश्नेन), and sevayā (सेवया) are instrumental singular. The instrumental answers "by what means." viddhi (विद्धि) does not take them as objects. tat (तत्) is the object, the knowledge. The three endings are the way. sevayā (सेवया) is the instrumental of a feminine आ-stem, sevā (सेवा), so the ending is --yā (या), not --ena (एन). Same case, different stem.

Say it back

The three means, in order. If one of them is missing, stay here. Prostration, question, service.