4.15

एवं ज्ञात्वा कृतं कर्म पूर्वैरपि मुमुक्षुभिः ।
कुरु कर्मैव तस्मात्त्वं पूर्वैः पूर्वतरं कृतम् ॥

evaṃ jñātvā kṛtaṃ karma pūrvair api mumukṣubhiḥ
kuru karmaiva tasmāt tvaṃ pūrvaiḥ pūrvataraṃ kṛtam

Kṛṣṇa (कृष्ण) is still speaking, to Arjuna.

The verse

Knowing this, the ancients who sought release also did action; therefore you too do action, the older deed done by those of old.

नेपालीमा

यो जानेर मुक्ति चाहने पुरानाहरूले पनि कर्म गरे। त्यसैले तिमी पनि पुरानाहरूले पहिले गरेको पुरानै कर्म गर।

Where it sits

4.14 was about not being bound, and this verse draws the conclusion Arjuna needs: the people who wanted release did not stop acting, so the order is kuru (कुरु). What that action is, and what inaction is, will be the problem of 4.16.

Split: एवम् + ज्ञात्वा + कृतम् + कर्म + पूर्वैः + अपि + मुमुक्षुभिः + कुरु + कर्म + एव + तस्मात् + त्वम् + पूर्वैः + पूर्वतरम् + कृतम्

evam + jñātvā + kṛtam + karma + pūrvaiḥ + api + mumukṣubhiḥ + kuru + karma + eva + tasmāt + tvam + pūrvaiḥ + pūrvataram + kṛtam

Sanskrit, in depth

The words

देवनागरी	Word	Grammar	Sense
एवम्	evam	indeclinable	thus. As 4.14 said.
ज्ञात्वा	jñātvā	gerund	having known.
कृतम्	kṛtam	nominative neuter	done. Agrees with karma (कर्म).
कर्म	karma	nominative	action.
पूर्वैः	pūrvaiḥ	instrumental plural	by the earlier ones, by the ancients.
अपि	api	indeclinable	even, also.
मुमुक्षुभिः	mumukṣubhiḥ	instrumental plural	by those who desire release. A desiderative from muc (मुच्), "release."
कुरु	kuru	imperative, 2nd singular	do. From kṛ (कृ).
कर्म	karma	accusative	action.
एव	eva	indeclinable	itself, that very.
तस्मात्	tasmāt	indeclinable, ablative	therefore.
त्वम्	tvam	nominative	you.
पूर्वैः	pūrvaiḥ	instrumental plural	by the ancients.
पूर्वतरम्	pūrvataram	accusative neuter	the more ancient one. Comparative of pūrva (पूर्व). Agrees with kṛtam (कृतम्).
कृतम्	kṛtam	accusative neuter	done.

The phrases

evaṃ jñātvā kṛtaṃ karma pūrvaiḥ api mumukṣubhiḥ (एवं ज्ञात्वा कृतं कर्म पूर्वैः अपि मुमुक्षुभिः) is the precedent. Knowing thus, action was done even by the ancients who wanted release. pūrvaiḥ api (पूर्वैः अपि) is pūrvair api (पूर्वैरपि). The gerund jñātvā (ज्ञात्वा) belongs to those ancients, the instrument of kṛtam (कृतम्).

kuru karma eva tasmāt tvam (कुरु कर्म एव तस्मात् त्वम्) is the order. Therefore you do that very action. karma eva (कर्म एव) is karmaiva (कर्मैव). tasmāt tvam (तस्मात् त्वम्) doubles the t (त्): tasmāt tvam (तस्मात्त्वम्). The subject tvam (त्वम्) sits after the imperative. It is still "you."

pūrvaiḥ pūrvataraṃ kṛtam (पूर्वैः पूर्वतरं कृतम्) describes the action he is told to do. The more ancient deed, done by the ancients. pūrvataram (पूर्वतरम्) before k (क्) is pūrvataraṃ (पूर्वतरं).

Sanskrit in this line

kuru (कुरु) is imperative, second person, "do." The subject tvam (त्वम्) can stand late and the order is still his. tasmāt tvam (तस्मात् त्वम्) is recited tasmāt tvam (तस्मात्त्वम्): a final t (त्) before another t (त्) is doubled, not lost. The comparative pūrvataram (पूर्वतरम्) is "more ancient," not a second group of people.

Say it back

What the ancients did, and what he is told to do. If kuru (कुरु) comes out as a past tense, stay here.