सक्ताः कर्मण्यविद्वांसो यथा कुर्वन्ति भारतकुर्याद् विद्वांस्तथाऽसक्तश्चिकीर्षुर्लोकसङ्ग्रहम्
In plain words
As the unwise act with attachment to action, Bharata, so should the wise act without attachment, desiring lokasaṅgraha—keeping the world from going astray.
Word for word
As the unwise, attached to action, act, O Bhārata, so should the wise one act, unattached, wishing to bring about the holding together of the world.
The commentators
Bhagavadgītābhāṣyam
यदि पुनः अहमिव त्वं कृतार्थबुद्धिः, आत्मवित् अन्यो वा, तस्यापि आत्मनः कर्तव्याभावेऽपि परानुग्रह एव कर्तव्य इत्याह —
सक्ताः कर्मणि ‘अस्य कर्मणः फलं मम भविष्यति’ इति केचित् अविद्वांसः यथा कुर्वन्ति भारत, कुर्यात् विद्वान् आत्मवित् तथा असक्तः सन् । तद्वत् किमर्थं करोति ? तत् शृणु — चिकीर्षुः कर्तुमिच्छुः लोकसङ्ग्रहम् ॥ २५ ॥
In plain words
But suppose you are like me: certain that the goal is already reached — a knower of the ātman, or anyone else of that kind. Even for such a person, even with nothing left to do for himself, one thing still remains to be done: the good of others, and only that. This is what he goes on to say —
The unknowing work while stuck to the work: 'the fruit of this deed will be mine.' That is how they act, Arjuna. And the knower — the one who knows the Self — should act exactly that way, only unattached. Same work, no grip. Then why does he act at all? Listen: cikīrṣuḥ, wishing to bring about — lokasaṅgraham, the holding-together of the world.
Close to the Sanskrit
But if you, like me, are one whose conviction is that the goal has been accomplished — a knower of the Self, or any other such person — then even for him, even in the absence of anything to be done for himself, kindness to others alone is to be done; thus he says —
Attached to action — 'the fruit of this action will be mine' — thus some, the unknowing, in the manner in which they act, O Bhārata, in that manner let the knower, the knower of the Self, act, being unattached. Like that. For what purpose does he act? Hear that: cikīrṣuḥ — wishing to bring about — lokasaṅgraham, the holding-together of the world.