"Just like Viśvāmitra. Viśvāmitra was being disturbed by some demons in the forest. They used to live in the forest. So Viśvāmitra was able to kill such demon, many demons, by his will. But he did not do so. He went to Mahārāja Daśaratha, father of Lord Rāmacandra, to request him that “Give your sons Rāma and Lakṣmaṇa. I will take them with me. They will kill that demon.” The killing is there, but the brāhmaṇa is not going to kill personally. Or the vaiśya is not meant for killing, neither the śūdras. Only the kṣatriyas. The kṣatriyas should be so trained up. Just like in USA there is some trouble in recruiting soldiers, because… Why the difficulty is? The difficulty is the training is like śūdras. The young men are trained up like śūdras, how they can fight? Therefore they are afraid (see pic above). They try to avoid fighting. Because there is no division. Everyone, in this age, everyone is śūdra. How you can expect a śūdra will be encouraged to fight? That is not possible. Therefore real social structure should be four divisions, brāhmaṇa, kṣatriya, vaiśya, śūdra. Brāhmaṇa, fully engaged for enlightenment of the people, knowledge, spiritual knowledge. They are meant for that. They will cultivate that knowledge personally, paṭhana pāṭhana, and make students. Brahminical class. Similarly kṣatriya. They should be trained up in politics, in fighting, not to flee away from fighting (see pic above). These are the training of the kṣatriyas."

Bhagavad-gītā 2.36-37
by His Divine Grace A. C. Bhaktivedanta Swami Prabhupāda
London, September 4, 1973
730904BG.LON

http://causelessmercy.com/t/t/730904BG.LON.htm