There is a class of men, they are called asuras. They are sura-dviṣām. They are always envious of the devotees. They are called demons. Just like Prahlāda Mahārāja and his father, Hiraṇyakaśipu. Hiraṇyakaśipu is the father of Prahlāda Mahārāja, but because Prahlāda Mahārāja was a devotee, he became envious. That is the nature of the demon. So much so envious that he was prepared to kill his own son. The only fault is that little boy, he was chanting Hare Kṛṣṇa. That is his fault. The father could not. Therefore they are called sura-dviṣām, always envious of the devotees. Demon means always envious of the devotee.
This material world is so nuisance place that . . . just you have got a very nice example: just like Jesus Christ, Lord Christ. So what was his fault? But the sura-dviṣām, the envious person, killed him. And if we find, if we analyze, what is the fault of Jesus Christ, there is no fault. The only fault he was preaching about God. And still we find so many enemies. He was cruelly crucified. So you'll always find this, sura-dviṣām. So Kṛṣṇa comes to kill these sura-dviṣām. Therefore vadhāya ca sura-dviṣām. These envious persons are killed.
But this killing business can be done without the presence of Kṛṣṇa. Because there are so many natural forces—war, pestilence, famine, anything—just set on working. Millions of people can be killed. So Kṛṣṇa does not require to come here to kill these rascals. They can be killed simply by Kṛṣṇa's direction, nature's law. Prakṛteḥ kriyamāṇāni guṇaiḥ karmāṇi sarvaśaḥ (BG 3.27). Sṛṣṭi-sthiti-pralaya-sādhana-śaktir ekā (Bs. 5.44). The nature has got so much power that it can create, it can maintain, it can annihilate, dissolute, everything. Nature is so powerful. Sṛṣṭi-sthiti-pralaya. Sṛṣṭi means creation, and sthiti means maintenance, and pralaya means destruction. These three things nature can do.