Janaka and other kings reached perfection through action, so you too should act for the world's good.

Advaita Vedānta

Action is preparatory: a means to purify the inner being, and the truly liberated continue to act only because of momentum, not because action liberates. These commentators carefully consider whether Janaka and the rest were already right-seers or not. If they had right vision, they kept acting while in knowledge, for the world's sake, because action had already begun for them (prarabdha). If they had not, then their action was the staged means to purification leading to knowledge. A distinctive sub-debate appears over who may renounce. One strand argues, from scriptural and traditional rules on the four life-stages, that formal renunciation (sannyasa, with its outward emblems) belongs properly to the brahmin alone, so a kshatriya like Arjuna is barred from it and must act. Another strand allows that a kshatriya may have an inward renunciation, the mere dropping of distracting actions even without the outward sign, citing examples like Bharata and Rshabha; on this view lokasangraha is not the principal purpose of action, and Arjuna in particular, not every kshatriya, is the one here enjoined to act.

Śaṅkarācārya · Śrī Ānandagiri · Madhusūdana Sarasvatī · Śrī Nīlakaṇṭha · Dhanapati Sūri

Viśiṣṭādvaita

The discipline of action (karma-yoga) is not merely preparatory but is positively the better path for beholding the self, even for one already qualified for the discipline of knowledge (jnana-yoga). Janaka and the royal sages, foremost among knowers, reached the self by karma-yoga itself. The word 'alone' (eva) here carries the non-discontinuation of karma-yoga even for the jnana-yoga-qualified, and is to be construed with 'you ought to act,' shutting out a turn to jnana-yoga. Lokasangraha is read as central, not auxiliary: the exemplary person's visible activity draws people into the same kind of right activity, and this is to be sustained until self-attainment. There is also a warning: to claim jnana-yoga fitness and abandon karma-yoga risks a double fall, both failing the world and, through the resulting fault, slipping even from the discipline of knowledge.

Rāmānujācārya · Vedānta Deśika

Bhedabheda

The word 'alone' is read as mere emphasis: it serves to exclude the absence of action, not to exclude knowledge. Janaka and the rest attained liberation by action. Yet a further note is sounded that the others do not press: in the highest sense action is to be performed for one's own sake, since knowledge by itself leads toward release. (The source breaks off before completing this clause, so its full force is left open.)

Śrī Bhāskara

Dvaita

Action by itself never liberates; release comes from direct knowledge of God alone, and action is only its means. The instrumental 'by action' must be read as 'along with action,' that is, while performing action, not 'by action as the cause of liberation.' Janaka and the rest first did action, then gained knowledge, and reached perfection by way of that knowledge; their being men of knowledge is well established in the epic and the Upanishads. Where scriptures seem to promise release by pilgrimage, bathing at sacred fords, or ritual alone, those texts are either praise (laudatory speech), or they mean release from sin rather than final liberation, or they point to such acts as merely a means toward the knowledge of Brahman. Without the knowledge of Brahman there is no release at all. The accompaniment of action even after liberation is understood as serving the increase of bliss in the liberated state.

Madhvācārya · Śrī Jayatīrtha

Śuddhādvaita

The accent falls on offering and on God's command rather than on personal attainment. For Vallabha, Janaka reached the state of the living-liberated through action itself; by the principle that one and the same act can serve two ends, action can yield both yoga and the perfection of knowledge. Janaka is the model of the kingly householder who, though perfectly knowing, performed every act in the spirit of offering, and the same path is open to the warrior whose battlefield is now his temple. Purushottama meets the devotee's special objection: Janaka had not taken refuge in the Lord, so unattached action suits him, but what of one who has surrendered? The answer is that, although for the Lord's devotee action is not strictly necessary, it is to be done by the Lord's command, for the upholding of the worlds, and never for any 'perfection' it might bring the devotee. Devotion stands; the work is simply maintenance of the order God has set in motion.

Vallabhācārya · Śrī Puruṣottama

Kashmir Shaivism

The comment is brief and offers only the plain point: Janaka and the rest stand as the examples of those who reached perfection while yet doing action.

Ācārya Abhinavagupta

Bhakti

Emphasis falls on the example set for others and on the duty of the realized to keep acting for the world's sake. Krishna cites the standard of right conduct (sad-acara). When the great one acts, all people will act; if the wise one casts action aside, the ignorant take him as their example and throw their own duties away and fall, so the protection of the world is the very fruit of the wise one's continued action. Even one who has beheld both his own Self and the supreme Self performs action for the holding-together of the world. Jnaneshwari gives the vivid image of a sighted man walking ahead on the road so that the blind who follow may find their way: in just this way the wise should take the ignorant along and teach them their duty, for if the wise do not act, how will the ignorant ever learn what their own duties are?

Śrīdhara Svāmī · Śrīla Viśvanātha · Śrīla Baladeva · Sant Jñāneśvar

Modern

These readings stress that lokasangraha is a positive ideal and that realization is no excuse to stop. Sivananda holds plainly that Janaka and others had perfect knowledge of the Self yet performed actions to set an example and guide the masses. Tilak argues that the second half of the verse opens a genuinely new and higher theme: securing universal welfare by one's action is a real ideal for the wise person to reach, not merely a grudging acceptance that action cannot be escaped; 'loka' here covers not just humankind but the whole world, to be maintained, fed, protected, and defended on a proper path. Ramsukhdas, reading non-sectarianly, notes that Janaka attained the Supreme even while performing a king's duties, because action done without attachment (asakti) is no obstacle to attaining God; so Arjuna too can attain the Supreme even in the duty of battle, and one who has already attained must keep doing his proper work, now for the world's sake and not his own.

Swami Sivananda · Lokmanya Tilak · Swami Ramsukhdas