"So Kṛṣṇa is addressing Arjuna, puruṣarṣabha, the best of the men. 'O the best of the men.' Certainly, Arjuna is the best of the mankind. Because he is directly friend of Kṛṣṇa, who can be better man than him? The best of the men. So the best of the men, why he's distressed in executing his duty? Therefore, this very word is used, that 'You are the best of the men.' Actually, the best of the men should not be disturbed by any material condition. He should discharge his duties. And what is the duty? Duty is to become immortal. This is the duty. The lowest of the men does not know how to become immortal, amṛta. Mṛta means death and amṛta means no death. The modern rascal civilization cannot understand that there is possibility of becoming immortal. They have taken it, accepted it; 'Well, who can stop?' They are simply scientifically calculating that 'Some day will come, by science, we shall be immortal, there will be no death.' The formula is given here by Kṛṣṇa how to become immortal. That means you should be callous of this so-called happiness and distress of this material world. That is the first qualification. One who doesn't care what is the distress and happiness of this body, he must execute Kṛṣṇa consciousness. That is the qualification. 'Oh, I cannot execute Kṛṣṇa consciousness because there are so many inconveniences,' he's not fit for becoming immortal.
People do not know that there can, we can become immortal. Immortal we are, but we have been embodied in this material body. Therefore we have to accept mortality, birth and death. These things stated in the Bhagavad-gītā, this is the beginning of spiritual life. Spiritual life means how to become immortal. They come to ask me, 'Sir, do you know some spiritual magic? Kuṇḍalinī, yoga? This? That?' All for material benefit. Spiritualist means something magic so that you can get some material benefit. If by stretching your hand you can get some little quantity of gold, then you are spiritualist: 'Oh, here is a man, wonderful spiritualist. He can create gold. He can cure disease by simply...' What is called? Fooing.(?) Like that. They want to see magic only for material benefit. What is called? Miracles. That is spiritualist. Spiritual life means how to become immortal. Amṛtatvāya. So 'mṛtatvāya kalpate. Kṛṣṇa has explained,
mātrā-sparśās tu kaunteya
tāṁs titikṣasva bhārata
Tāṁs titikṣasva. Don't be disturbed by the sensuous disturbance of the body. Become dhīra. Dhīras tatra na muhyati (BG 2.13). Become dhīra.
So one who has practiced to become dhīra, not to become disturbed by the sensuous or bodily sensations, he's supposed to be kalpate, he's supposed to be, to become immortal at the end. And the Bhāgavata says also that you do not become a spiritual master, you do not become a father, you do not become a mother, you do not become a friend, a relative, in this way, if you cannot make your subordinate immortal. Pitā na sa syāt, gurur na sa syāt, gurur na sa syāt, jananī na sā syāt pitā na sa syāt. In this way, there is a list. You become father of hundreds of children. That's all right. No restriction. You beget children. But you must make your children immortal. That is the injunction. You have become guru. That's all right, Guruji Mahārāja. That's all right. But make your disciples immortal. Otherwise, don't, don't cheat others. Cheaters. Illicit father, illicit mother. As we say, illicit sex. Similarly illicit father, illicit mother. Who is illicit father, illicit mother? Who cannot make his children immortal. That is the aim of human life. How to become immortal. How... Not to become, we are immortal. Just like a person, he's diseased, attacked by fever. Fever is not his natural condition, but somehow or other, he has got fever. Similarly, we are immortal. That will be explained. Na jāyate na mriyate vā. The living entity never takes birth, never dies. Therefore immortal. Immortal means no birth, no death. That is immortal. Whenever there is birth, there is death. If there is no birth, there is no death. That is immortality. So the whole scheme is Vedic scheme, not otherwise: how to become immortal."
(Srila Prabhupada Lecture, London, August 21, 1973)