Lecture given by Prahladananda Swami on Srimad Bhagavatam, Canto 7, Chapter 15, Text 34.
When the yogi regularly practices in this way, in a short time his heart becomes fixed and free from disturbance, like a fire without flames or smoke.
Nirvana means the cessation of all material desires. Sometimes desirelessness is understood to imply an end to the workings of the mind, but this is not possible. The living entity has senses, and if the senses stopped working, the living entity would no longer be a living entity; he would be exactly like stone or wood. This is not possible. Because he is living, he is nitya and cetana — eternally sentient. For those who are not very advanced, the practice of yoga is recommended in order to stop the mind from being agitated by material desires, but if one fixes his mind on the lotus feet of Krishna, his mind naturally becomes peaceful very soon. This peace is described in Bhagavad-gita (5.29):
jnatva mam santim ricchati
If one can understand Krishna as the supreme enjoyer, the supreme proprietor of everything, and the supreme friend of everyone, one is established in peace and is free from material agitation. However, for one who cannot understand the Supreme Personality of Godhead, the practice of yoga is recommended.