(Click to enlarge painting of Krishna and Arjuna on the Battlefield of Kurukshetra)
"So Kṛṣṇa is advising Arjuna that 'This fight is not ordinary fight. It is dharma-yuddha, and you should accept it; you should not hesitate. After all, the soul is never killed. It is the duty, it is the duty of different dharma.' Sva-dharma. Sva-dharma means so long one is in the bodily concept of life... This sva-dharma means this brāhmaṇa, kṣatriya, vaiśya, śūdra. This is sva-dharma. And Arjuna belonged to the kṣatriya; therefore his sva-dharma, his occupational duty, is to fight. So... And real sva-dharma is spiritual sva-dharma. In the spiritual, so when you go deep into the matter, when you understand that 'I am not this body; I am soul,' then that is real sva-dharma. And what is the occupation of that sva-dharma? That is to be engaged in the service of the Lord. Jīvera svarūpa haya nitya-kṛṣṇa-dāsa (CC Madhya 20.108-109). Actually that is sva-dharma. Every soul is eternally servant of Kṛṣṇa. That is spiritual sva-dharma. And material sva-dharma means this brāhmaṇa, kṣatriya, vaiśya, śūdra.
Therefore the sva-dharma changes. Sva-dharma changes as soon as one is elevated to the spiritual platform. That is explained in the Bhagavad-gītā: sa guṇān samatītya etān brahma-bhūyāya kalpate (BG 14.26). Who? Brahma-bhūyāya kalpate: one who is engaged in devotional service. A devotee's position is transcendental. He has no..., no more sva-dharma in the bodily concept of life, because he's neither brāhmaṇa, neither kṣatriya, nor vaiśya, nor śūdra. Caitanya Mahāprabhu has said that 'I am not a brāhmaṇa. I am not a śūdra. I am not a kṣatriya. I am not a brahmacārī. I am not a sannyāsī.' In this way He negativated all the eight items, because sva-dharma means varṇāśrama dharma. Varṇa and āśrama. Four castes: brāhmaṇa, kṣatriya, vaiśya, śūdra.
And four spiritual order: brahmacārī, gṛhastha, vānaprastha and sannyāsa. So Caitanya Mahāprabhu denied, that 'I am not this, I am not this, I am not that, I am not that.' Then what You are? Gopī-bhartuḥ pada-kamalayor dāsa-dāsānudāsaḥ (CC Madhya 13.80). Jīvera svarūpa haya nitya-kṛṣṇa-dāsa (CC Madhya 20.108-109). Gopī-bhartuḥ means this maintainer of the gopīs, Kṛṣṇa. Gopī-bhartuḥ. Gopī-bhartuḥ pada-kamalayoḥ: 'I am the servant of the servant of the servant of the servant who is engaged in the service of the lotus feet of Kṛṣṇa.'
So this is... Those who are in Kṛṣṇa consciousness, those who have decided to serve Kṛṣṇa only, they are no longer in the categories of sva-dharma, the bodily sva-dharma, brāhmaṇa, kṣatriya, vaiśya, śūdra, or brahmacārī, vānaprastha. He is transcendental. That is confirmed in every śāstra. So, so far we are concerned, Kṛṣṇa conscious, so long our bodily concept of life is not completely eradicated, we must follow the sva-dharma of the body: brāhmaṇa, kṣatriya, vaiśya, śūdra, ity ādi. But when actually advanced, that is mahā-bhāgavata. We should not imitate that, but our process is the more we advance in Kṛṣṇa consciousness, we become transcendental to this bodily concept of life, brāhmaṇa, kṣatriya, vaiśya, śūdra. But Kṛṣṇa says,
māṁ ca 'vyabhicāreṇa
bhakti-yogena yaḥ sevate
sa guṇān samatītyaitān
So anyone who engages himself, without any reservation, to the service of the Lord, he is not within the category of these eight varṇāśrama-dharma. He's transcendental. Sa brahma-bhūyāya kalpate. So as a Kṛṣṇa consciousness person, he can act like anything by the order of Kṛṣṇa. He can act as a brāhmaṇa, he can act as a śūdra—because his main business is to carry out Kṛṣṇa's order. He's no longer within the category of this sva-dharma. So Kṛṣṇa, asking Arjuna, that 'If you are thinking in the bodily concept of life, then also...' Means, 'First of all, when I have ordered, I have sanctioned, you can work it beyond the bodily concept of life. But if you are thinking still that you are in the bodily concept of life, then, as a kṣatriya, it is your duty to fight.'
Kṛṣṇa is trying to put Arjuna in the dilemma, 'This way or that way, you must have to fight. If you think that you are not in bodily concept of life, then it is My order, "You must fight." And if you think that you are in bodily concept of life, then you are a kṣatriya, you must fight. Both ways you have to fight.' This is Kṛṣṇa's conclusion."
(Srila Prabhupada Lecture, London, September 1, 1973)