4.12

काङ्क्षन्तः कर्मणां सिद्धिं यजन्त इह देवताः ।
क्षिप्रं हि मानुषे लोके सिद्धिर्भवति कर्मजा ॥

kāṅkṣantaḥ karmaṇāṃ siddhiṃ yajanta iha devatāḥ
kṣipraṃ hi mānuṣe loke siddhir bhavati karmajā

Kṛṣṇa (कृष्ण) is still speaking, to Arjuna.

The verse

Those who want the success of their actions sacrifice here to the gods; in the human world, success born of action comes quickly.

नेपालीमा

कर्मको सिद्धि चाहनेहरू यहाँ देवतालाई यज्ञ गर्छन्। मनुष्यलोकमा कर्मबाट जन्मेको सिद्धि छिटो आउँछ।

Where it sits

4.11 said he meets every way of coming, and this verse names the way that wants a result soon, placed rather than condemned. The next verse will say who set up the order those acts sit in, and will refuse the idea that the maker is bound by them.

Split: काङ्क्षन्तः + कर्मणाम् + सिद्धिम् + यजन्तः + इह + देवताः + क्षिप्रम् + हि + मानुषे + लोके + सिद्धिः + भवति + कर्म-जा

kāṅkṣantaḥ + karmaṇām + siddhim + yajantaḥ + iha + devatāḥ + kṣipram + hi + mānuṣe + loke + siddhiḥ + bhavati + karma-jā

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
काङ्क्षन्तःkāṅkṣantaḥpresent participle, nominative pluraldesiring. From kāṅkṣ (काङ्क्ष्). The people are the subject.
कर्मणाम्karmaṇāmgenitive pluralof actions.
सिद्धिम्siddhimaccusativesuccess, the fulfillment of the act.
यजन्तःyajantaḥpresent participle, nominative pluralsacrificing, worshipping. From yaj (यज्).
इहihaindeclinablehere.
देवताःdevatāḥaccusative pluralthe gods. Object of yajantaḥ (यजन्तः), not the subject.
क्षिप्रम्kṣipramaccusative used as adverbquickly.
हिhiindeclinablefor, indeed.
मानुषेmānuṣelocative singularin the human. Agrees with loke (लोके).
लोकेlokelocative singularin the world.
सिद्धिःsiddhiḥnominativesuccess.
भवतिbhavatipresent, 3rd singularcomes to be.
कर्म-जाkarma-jānominative feminineborn of action. Agrees with siddhiḥ (सिद्धिः).

The phrases

kāṅkṣantaḥ karmaṇāṃ siddhiṃ yajantaḥ iha devatāḥ (काङ्क्षन्तः कर्मणां सिद्धिं यजन्तः इह देवताः) is the ordinary approach. Desiring the success of their actions, they sacrifice here to the gods. The two participles are the subject. devatāḥ (देवताः) is what they worship. yajantaḥ iha (यजन्तः इह) is recited yajanta iha (यजन्त इह): aḥ (अः) before a vowel other than a (अ) drops, and the remaining a (अ) does not merge with i (इ).

kṣipraṃ hi mānuṣe loke siddhiḥ bhavati karmajā (क्षिप्रं हि मानुषे लोके सिद्धिः भवति कर्मजा) is why they do it. In the human world, success born of action comes quickly. siddhiḥ bhavati (सिद्धिः भवति) is siddhir bhavati (सिद्धिर्भवति).

Sanskrit in this line

yajantaḥ (यजन्तः) is nominative, the people who sacrifice. devatāḥ (देवताः) is accusative, the gods they sacrifice to. The endings look alike, --aḥ (अः) and --āḥ (आः), and the object sits at the end of the line. If you make the gods the subject, the participle has nobody left to agree with. kāṅkṣantaḥ (काङ्क्षन्तः) is the same nominative plural, desiring the success, not desiring the gods.

Say it back

Who sacrifices, to whom, and what comes of it quickly. If devatāḥ (देवताः) is said as the subject, stay here.