The threefold loss in refusing the righteous war.

Advaita Vedānta

This reading first removes Arjuna's own earlier objection. Arjuna had said he did not want victory or even the three worlds, so why fight at all? The answer is that the fault lies in NOT fighting: the lawful war is undefiled by the fault of injury because it keeps the rules of the good, such as Manu's, that one must not slay with treacherous weapons, nor one fallen, nor a suppliant, nor one who says 'I am yours'. Acting against the scripture-forbidden withdrawal brings only sin, never dharma and fame. This reading then adds a second, decisive argument the others do not develop: since these aggressors will surely kill Arjuna once he turns his back, fleeing does not even spare him. Citing Manu, that one who turns back in fear and is slain takes on whatever demerit his master carries, and Yajnavalkya, that the king takes the merit of those slain in flight, it concludes that retreat would make Arjuna forfeit his own long-gathered merit and absorb others' sin. By this whole train, Arjuna's earlier fear that 'sin alone would cling by slaying these aggressors' is explicitly set aside.

Madhusūdana Sarasvatī

Viśiṣṭādvaita

This school reads the verse with close grammatical care to fix exactly who and what it binds. The refusal springs from 'moha', delusion, defined precisely as the confusion that takes dharma to be adharma. The word 'you' is read as a qualifier marking the kshatriya in particular: withdrawing from war brings no sin to brahmanas and others, so the warning is station-specific. The word 'this' is read as 'already begun', for if mere non-undertaking of war were the fault, the verse would absurdly prescribe permanent, endless war; the sin lies in abandoning the duty once it has actually commenced. The phrase about the fruit of one's duty is read with 'dharma' standing for its fruit, otherwise the word would be empty repetition. On this reading the stakes are 'niratishaya', unsurpassed: the happiness forfeited is unsurpassed happiness, the fame is the unsurpassed fame that comes with victory, and the sin incurred is the cause of unsurpassed pain. So both the seen good and the unseen good are lost, and supreme suffering is taken on.

Rāmānujācārya · Vedānta Deśika

Kashmir Shaivism

This reading uses the verse as an argument from the lesser to the greater. Even ordinary kshatriyas, still 'made of desire' and acting for reward, ought not to give up a war of this kind, since it is a cause of heaven. How much less, then, should one to whom this higher knowledge has been taught give it up. That is the verse's force. But this source adds a careful limit the heaven-centered readings do not: the verse does not actually terminate in heaven as its final aim. The promise of heaven is real but is not the Gita's last word, and this teaching points beyond it.

Ācārya Abhinavagupta

Bhedabheda

This reading frames the righteous war as an open, unbarred gateway to heaven, a reward brought without effort and simply set before Arjuna. It then presses a striking qualification: such a war falls only to the fortunate, the 'happy', the partakers of happiness, and not to others. Read another way, it falls to those who shrink from hardship. The plain import is that to refuse this gift is the mark of the ill-fated, of one who has let an effortless door to heaven swing open and then walked away from it.

Śrī Bhāskara

Bhakti

These devotional readings concretize the loss. One specifies that the fame to be won is the fame of slaying foes like Nivatakavacha, a renown that pleases Rudra, and that the sin incurred is precisely the abandonment of one's own duty as forbidden by tradition, by texts such as 'one who does not turn back from battle'. The other paints the consequence in vivid images: to lay down arms is to court your own disaster and voluntarily lose the fame your ancestors won; your existing fame wanes, the whole world censures you, and grave sins seek you out and cling. As a widow is insulted everywhere, and as vultures mangle from every side a corpse left in the forest, so do great sins devour a man who has abandoned the duty that was his own.

Śrīla Baladeva · Sant Jñāneśvar

Modern

This reading first reframes the 'if' itself. Arjuna will not in fact be able to stay out of the fight: helpless before his warrior-nature, his kshatra-svabhava, he will surely fight in the end, as the Gita itself later says. So the condition 'if you do not fight' is only a supposition, granted for the sake of argument. Granting it, the consequences still hold. Renouncing the duty that has come to him of itself, he would be forced to take up another's duty instead, and sin attaches from that. And the destruction of his fame is given a precise, human cause: if Arjuna withdraws, people will conclude that even so great a hero grew afraid of dying, and on that judgment his renown is destroyed.

Swami Ramsukhdas