3.20

कर्मणैव हि संसिद्धिमास्थिता जनकादयः ।
लोकसंग्रहमेवापि सम्पश्यन्कर्तुमर्हसि ॥

karmaṇaiva hi saṃsiddhim āsthitā janakādayaḥ
lokasaṃgraham evāpi sampaśyan kartum arhasi

śrībhagavān (श्रीभगवान्) is speaking, and he puts Janaka (जनक) beside the rule of 3.19.

The verse

By action alone Janaka (जनक) and the others reached perfection; you too ought to act, looking even to the holding-together of the world.

नेपालीमा

कर्मले नै जनक र अरूहरू सिद्धिमा पुगे। संसारलाई एकसाथ राख्ने काम हेरेर पनि तिमीले कर्म गर्नुपर्छ।

Where it sits

The man of 3.17 needed no reason outside himself, and Arjuna (अर्जुन) is given two: the precedent of Janaka (जनक), and the world that comes apart if the visible people stop. 3.21 says why the person in front cannot stop.

Split: कर्मणा + एव + हि + संसिद्धिम् + आस्थिताः + जनक-आदयः + लोक-संग्रहम् + एव + अपि + सम्पश्यन् + कर्तुम् + अर्हसि

karmaṇā + eva + hi + saṃsiddhim + āsthitāḥ + janaka-ādayaḥ + loka-saṃgraham + eva + api + sampaśyan + kartum + arhasi

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
कर्मणाkarmaṇāinstrumental of karman (कर्मन्)by action.
एवevaindeclinablealone.
हिhiindeclinableindeed.
संसिद्धिम्saṃsiddhimaccusativeperfection, full arrival.
आस्थिताःāsthitāḥnominative pluralhaving reached, standing upon. From ā-sthā (आ-स्था).
जनक-आदयःjanaka-ādayaḥnominative pluralJanaka (जनक) and the others. ādi (आदि) is "and the rest."
लोक-संग्रहम्loka-saṃgrahamaccusativethe holding-together of the world, the keeping of people.
एवevaindeclinableindeed.
अपिapiindeclinablealso, even.
सम्पश्यन्sampaśyanpresent participle, nominativeseeing, looking toward.
कर्तुम्kartuminfinitive of kṛ (कृ)to do.
अर्हसिarhasipresent, 2nd singular of arh (अर्ह्)you ought.

The phrases

कर्मणा एव हि संसिद्धिम् आस्थिताः जनकादयः karmaṇaiva hi saṃsiddhim āsthitāḥ janakādayaḥ is the precedent. By action alone, Janaka and the others reached perfection. आ + ए ā + e has made karmaṇaiva (कर्मणैव). āsthitāḥ (आस्थिताः) before the voiced j (ज्) is āsthitā (आस्थिता).

लोकसंग्रहम् एव अपि सम्पश्यन् कर्तुम् अर्हसि lokasaṃgraham evāpi sampaśyan kartum arhasi is the application. You too ought to act, looking even to the holding-together of the world. एव + अपि eva + api is evāpi (एवापि). sampaśyan (सम्पश्यन्) agrees with the tvam (त्वम्) inside arhasi (अर्हसि).

Sanskrit in this line

कर्तुम् अर्हसि kartum arhasi is "you ought to do." The infinitive in --tum (तुम्) names the act, and arhasi (अर्हसि) names the obligation. The subject is the person spoken to. sampaśyan (सम्पश्यन्) is not a second command. It is how he is to look while he does the act.

Say it back

Who reached the end by action, and what Arjuna (अर्जुन) is told to look at while he acts. If lokasaṃgraham (लोकसंग्रहम्) becomes "fame," stay here.