According to Vedic culture, anyone who does not follow the regulative principles observed by the higher castes (the brāhmaṇas, kṣatriyas and vaiśyas) or even those observed by the laborer class (the śūdras) is called a mleccha or yavana. The Vedic social situation is so planned that persons accepted as śūdras can gradually be elevated to the position of brāhmaṇas by the cultural advancement known as saṁskāra, or the purificatory process. The verdict of the Vedic scriptures is that no one becomes a brāhmaṇa or a mleccha simply by birth; by birth everyone is accepted as a śūdra. One has to elevate himself by the purificatory process to the stage of brahminical life. If he doesn’t, if he degrades himself further, he is then called a mleccha or yavana. Kālayavana belonged to the class of mlecchas and yavanas. Contaminated by sinful activities, he could not approach Kṛṣṇa. The principles from which higher-class men are restricted, namely illicit sexual indulgence, meat-eating, gambling and intoxication, are an integral part of the lives of the mlecchas and yavanas. Being bound by such sinful activities, one cannot make any advancement in God realization. The Bhagavad-gītā confirms that only one who is completely freed from all sinful reactions can engage in devotional service, or Kṛṣṇa consciousness.
When Kṛṣṇa entered the cave of the hill, Kālayavana followed, chastising Him with various harsh words. Kṛṣṇa suddenly disappeared from the demon's sight, but Kālayavana followed and also entered the cave. The first thing he saw was a man lying down asleep within the cave. Kālayavana was eager to fight with Kṛṣṇa, and when he could not see Kṛṣṇa but instead saw only a man lying down, he thought that Kṛṣṇa was sleeping within the cave. Kālayavana was very much puffed up and proud of his strength, and he thought Kṛṣṇa was avoiding the fight. Therefore, he strongly kicked the sleeping man, thinking him to be Kṛṣṇa. The sleeping man had been lying down for a very long time. When awakened by the kicking of Kālayavana, he immediately opened his eyes and began to look around in all directions. At last he saw Kālayavana standing nearby. The man had been untimely awakened and was therefore very angry, and when he looked upon Kālayavana in his angry mood, rays of fire emanated from his eyes, and Kālayavana burned to ashes within a moment.