Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 20


अस्त्येव राजन् भवतो मधुद्विष:पादारविन्दस्य गुणानुवादने ।रतिर्दुरापा विधुनोति नैष्ठिकीकामं कषायं मलमन्तरात्मन: ॥ २० ॥


asty eva rājan bhavato madhudviṣaḥpādāravindasya guṇānuvādaneratir durāpā vidhunoti naiṣṭhikīkāmaṁ kaṣāyaṁ malam antar-ātmanaḥ


Sanat-kumāra continued: My dear King, you already have an inclination to glorify the lotus feet of the Supreme Personality of Godhead. Such attachment is very difficult to achieve, but when one has attained such unflinching faith in the Lord, it automatically cleanses lusty desires from the core of the heart.


By association with devotees, dirty things within the heart of a materialistic man are gradually washed away by the grace of the Supreme Personality of Godhead. As silver becomes shiny by being polished, the heart of a materialistic person is cleansed of lusty desires by the good association of devotees. Actually the living being has no connection with this material enjoyment nor with lusty desires. He is simply imagining or dreaming while asleep. But by the association of pure devotees he is awakened, and immediately the spirit soul is situated in his own glory by understanding his constitutional position as the eternal servant of the Lord. Pṛthu Mahārāja was already a self-realized soul; therefore he had a natural inclination to glorify the activities of the Supreme Personality of Godhead, and the Kumāras assured him that there was no chance of his falling victim to the illusory energy of the Supreme Lord. In other words, the process of hearing and chanting about the glories of the Lord is the only means to clarify the heart of material contamination. By the process of karma, jñāna and yoga, no one will succeed in driving away contamination from the heart, but once a person takes to the shelter of the lotus feet of the Lord by devotional service, automatically all dirty things in the heart are removed without difficulty.