karmaṇaiva hi saḿsiddhim
āsthitā janakādayaḥ
loka-sańgraham evāpi
sampaśyan kartum arhasi

Translation of Bhagavad Gita 3.20

Kings such as Janaka attained perfection solely by performance of prescribed duties. Therefore, just for the sake of educating the people in general, you should perform your work.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

Kings like Janaka were all self-realized souls; consequently they had no obligation to perform the prescribed duties in the Vedas. Nonetheless they performed all prescribed activities just to set examples for the people in general. Janaka was the father of Sita and father-in-law of Lord Sri Rama. Being a great devotee of the Lord, he was transcendentally situated, but because he was the king of Mithila (a subdivision of Bihar province in India), he had to teach his subjects how to perform prescribed duties. Lord Krishna and Arjuna, the Lord’s eternal friend, had no need to fight in the Battle of Kurukshetra, but they fought to teach people in general that violence is also necessary in a situation where good arguments fail. Before the Battle of Kurukshetra, every effort was made to avoid the war, even by the Supreme Personality of Godhead, but the other party was determined to fight. So for such a right cause, there is a necessity for fighting. Although one who is situated in Krishna consciousness may not have any interest in the world, he still works to teach the public how to live and how to act. Experienced persons in Krishna consciousness can act in such a way that others will follow, and this is explained in the following verse.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

He gives proof of such actions in the first part of the verse. In the second part of the verse he says that if you think that you are qualified for jnana, even then, you should perform action it order to teach the people.

 Commentary by Sri Ramanuja of Sri Sampradaya:

3.20 It is also declared that Karma Yoga alone Janaka and others reached perfection. Because, Karma Yoga is the best means for securing the vision of the self even for a person who is qualified for Jnana Yoga, royal sages like Janaka and others, who are foremost among the Jnanins, preferred Karma Yoga as the means for attaining perfection. Thus, having first declared previously that Karma Yoga must be practised by an aspirant for release who is qualified for Karma Yoga alone, as he is unfit for Jnana Yoga, it was next stated with reasons that, even for one who is qualified for Jnana Yoga, Karma Yoga is better than Jnana Yoga Now it is going to be declared (in verses 20-26) that Karma Yoga must be performed in every way by one who is virtuous. At least for the guidance of the world, you should do work even if there is no need of it for yourself.

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

The understanding that the eternal soul is never slain is being confirmed by its freedom from the six changes of material existence being: birth, existence, growth, modification, decay and death which are controlling all living entities high and low in the material existence. The Supreme Lord by declaring the eternal soul is not born confirms the absence of any birth and by declaring the eternal soul does not die confirms the absence of any destruction. The word va occurring twice is used in the sense of and as in and the immortal soul does not come into existence by birth. The immortal soul is already by nature itself eternal. So existence by conception is proven false due to the fact the eternal soul is birthless. That which is conceived attains existence after birth; but that which already eternally exists by its own nature cannot be conceived again. This is the purport of this verse. Constant means not subject to modification. This confirms the absence of growth. Eternal confirms the absence of decay. Ancient confirms the absence of ageing ever beyond time the eternal soul is ageless. Thus there is never a repetition regarding the existence of the eternal soul and the six changes of the physical of birth, existence, growth, modification, decay and death mentioned by Yaksa and other expounders of the Vedic scriptures as to the nature of things in this world never is applicable to the eternal soul which factually every living entity born from a womb possesses. The imperishable nature of the soul and the fact that the six changes of the physical body have no influence on it which is the topic presently under discussion has now been satisfactorily concluded and so it is confirmed that the eternal soul does not perish when the body perishes.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Here to emphasise the authority of the Vedic scriptures the Supreme Lord Krishna uses the words na jayate meaning never takes birth. The knowledge of the Lord is not born nor does it cease to be in the literal sense of the words. In all situations, time and places as well as in all stages it is never subject to modification. Nor is the knowledge of the soul ever subject to destruction and this is fully established in the Vedic scriptures. How one may ask? Due to the attributes like ajah the unborn referring to the Supreme Lord, sasvatah means permanent signifying that He remains in His spiritual form of consciousness and bliss without any modification, puranam means that the eternal embodied soul acquires another pura or body. Thus it can be understood that the soul is not ever destroyed even when the physical body perishes.

Now begins the summation.

The living entity and the Supreme Lord are both irrevocably established as unborn, eternal and indestructible. The Supreme Lord possessing a spiritual body does not come into existence by being associated with the material manifestation; but is eternally existing independently. Death correctly comprehended is merely the separation of the embodied soul from the physical body leaving it lifeless. Since for the Supreme Lord there is never any destruction of His form, there cannot be any connection to death by Him.

The eternal soul is also unborn and indestructible, otherwise creation could be considered simply a repetitive exercise going on and on absent of purpose. The eternal soul is also permanent but the eternal soul never exists independently; it has limited power, limited knowledge, incomplete in itself, dependent upon the transcendental energy of the Supreme Lord. In juxtaposition to that are the sublime attributes of the Supreme Lord who is omnipotent, omniscient and omnipresent. These are the natural attributes of the 2 there is no modifications to be found in them. Therefore the holy sages and rishi’s designated them both as sasvatah or permanent. Thus in the Visnu Purana because the living entity is embodied in countless bodies from the beginning of time it is known as puranah meaning ancient.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

As to questions of how the soul is neither the instigator of any actions or the recepient of any actions, Lord Krishna explains that the soul being eternal is not subject to the six modifications of material existence which are: birth, being, growth, transformation, dimunition and death. The soul is never born and never dies at any time. How can this be? It is not that the soul did not exist before and will not exist in the future. The soul exists eternally but opting the experiences of the material existence accepts a physical body. What did not exist in the past but is manifested only in the present is called conceived and that which exists now but will cease to exist eventually is called dead. But the soul is not conceived as it eternally exists and it will never die because it is immortal. With the 2 words ajah meaning unborn and nityah meaning eternal, it is made clear that the 2 modifications of birth and death are not applicable in regards to the soul. In order to also negate the idea of the soul posessing any modifications by even being, Lord Krishna explains that the soul is everlasting which means it is free from being or unbeing. The modification of any growth of the soul is neutralisd by the word puranah meaning ancient, that it always existed as it is. One posessing a body grows by the increase of the bodily parts; but the soul being bodiless does not increase it is the same eternally. The remaining 2 modifications of transformation and dimunition are rendered inapplicable by inference in understanding that the soul being eternal without any need to increase remains as it is and is changeless. Hence the soul being bereft of any of the six modifications of the physical body can never be destroyed even when the physical body is destroyed.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

3.20 Hi, for; in the olden days, the leaned Ksatriyas, janakadayah, Janaka and others such as Asvapati; asthitah, strove to attain; samsiddim, Liberation; karmana eva, through action itself. If it be that they were possessed of the fullest realization, then the meaning is that they remained established in Liberation whlile continuing, because of past momentum, to be associated with action itself-without renouncing it-with a veiw to preventing mankind from going astray. Again, if (it be that) Janaka and others had not attained fullest realization, then, they gradually became established in Liberation through action which is a means for the purification of the mind. The verse is to be explained thus. On the other hand, if you think, ‘Obligatory duty was performed even by Janaka and others of olden days who were surely unenlightened. [Ajanadbhih: This is also translated as, ‘surely because they were unenlightened’.-Tr.] There by it does not follow that action has to be undertaken by somebody else who has the fullest enlightenment and has reached his Goal’, nevertheless, tvam, you, who are under the influence of past actions; arhasi, ought; kartum, to perform (your duties); sampasyan api, keeping also in view; loka-sangraham, [V.S.A gives the meanings of the phrase as ‘the welfare of the world’, and ‘propitiation of mankind’.-Tr. ] the prevention of mankind from going astray; even that purpose. By whom, and how, is mankind to be prevented from going astray? That is being stated: [In Ast. this introductory sentence is as follows:loka-samgrahah kimartham kartavyam iti ucyate.-Tr.]

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

3.20 Karman=aiva etc. Therefore, janaka and others are examples for the fact that emancipation is even for those who perform action.

Sanskrit Shloka Without Transliteration Marks:

karmanaiva hi samsiddhim
asthita janakadayah
loka-sangraham evapi
sampasyan kartum arhasi

Sanskrit to English Word for Word Meanings:

karmaṇā — by work; eva — even; hi — certainly; saḿsiddhim — in perfection; āsthitāḥ — situated; janaka-ādayaḥ — Janaka and other kings; loka-sańgraham — the people in general; eva api — also; sampaśyan — considering; kartum — to act; arhasi — you deserve.