Due to our material association since time immemorial, we have accumulated heaps of dirty things in our minds. The total effect of this takes place when a living entity identifies himself with his body
SB Canto 4
When a devotee takes shelter at the lotus feet of the Supreme Personality of Godhead, he is completely cleansed of all misunderstanding or mental speculation, and he manifests renunciation. This is possible only when one is strengthened by practicing bhakti-yoga. Once having taken shelter at the root of the lotus feet of the Lord, a devotee never comes back to this material existence, which is full of the threefold miseries.
As stated by Lord Caitanya Mahāprabhu in His Śikṣāṣṭaka instructions, by the chanting of the holy name of the Lord—Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare—or by the process of hearing and chanting of the glories of the Lord, one's mind is gradually cleansed of all dirt. Due to our material association since time immemorial, we have accumulated heaps of dirty things in our minds. The total effect of this takes place when a living entity identifies himself with his body and is thus entrapped by the stringent laws of material nature and put into the cycle of repeated birth and death under the false impression of bodily identification. When one is strengthened by practicing bhakti-yoga, his mind is cleansed of this misunderstanding, and he is no longer interested in material existence or in sense gratification.
Bhakti, or devotional service, is characterized by vairāgya and jñāna. Jñāna refers to understanding that one is not his body, and vairāgya means disinterest in sense gratification. These two primary principles of separation from material bondage can be realized on the strength of bhakti-yoga. Thus when a devotee is fixed in the loving service of the lotus feet of the Lord, he will never come back to this material existence after quitting his body, as confirmed in Bhagavad-gītā by the Lord (tyaktvā dehaṁ punar janma naiti mām eti so 'rjuna (BG 4.9)).