So the effect of Kurukṣetra, dharma-kṣetra, was visible in the person of Arjuna, not in the person of Duryodhana. That is the difference. Therefore he was crying: "So I am put in such a position that I have to fight and I have to kill my brothers, my nephews, my grandfather." He was too much affected. Although it is weakness, but it is not actually weakness, it is compassion. Arjuna was not a coward, neither he was less heroic than the other side. But out of compassion, because he was devotee.
Devotees, they are para-duḥkha-duḥkhī (Vilāpa-kusumāñjali, 6). The, the symptom of a devotee is they are unhappy by seeing others unhappy. That is the symptom of devotee. Generally a person, if he sees somebody happy, he becomes unhappy. Mātsaratā. That is the world situation. If I see my brother is very happy, he has improved his material condition, then I become unhappy—"He has advanced so much, and I could not do so." This is material civilization.
Material civili . . . envious, gṛhamedhī. Everyone is envious. Either you take person to person or neighbor to neighbor, their sympathy is lip sympathy. Actually, everyone is envious: businessman to businessman, nation to nation. This is material world. Therefore spiritual advancement means for person who is not envious. Not envious.
Paramo nirmatsarāṇāṁ satāṁ vastavya-vastu vedyam (SB 1.1.2). In the Śrīmad-Bhāgavatam it is said that if you want to know the real truth, vastavya-vastu, then one must become paramo nirmatsaram. Nirmatsara. Matsara, matsara means envious, and nirmatsara, not envious. And parama, first-class nirmatsara.
Therefore Vyāsadeva says that dharmaḥ projjhita-kaitavo 'tra paramo nirmatsarāṇām (SB 1.1.2). In the introduction of Śrīmad-Bhāgavatam, Vyāsadeva says who are the candidates to understand this science of God, Śrīmad-Bhāgavatam. It is not for the persons who are entangled in cheating religious system. Cheating, dharmaḥ kaitavaḥ. Kaitava means cheating.
So cheating type of religious system are kicked out from this book, Śrīmad-Bhāgavatam, but it is meant for persons who are not envious, paramo nirmatsarāṇāṁ satām. Vastavya-vastu: one who wants to learn real reality, not false reality. This, here, in this material world, everything is false reality.
Just like we are trying to find out water in the desert. That is the example, mirage, false . . . there is no water. But the animal, he sees that there is water, vast water, and he runs after it and dies.
So here in this material also, world, every one of us, running after the false mirage that, "There is happiness, there is happiness, there is happiness." This is called material condition, and we are envious. This is the position, and therefore Kṛṣṇa begins the Bhagavad-gītā to get out of this ignorance and enviousness, and this is the basic principle of Bhagavad-gītā.