Srimad-Bhagavatam: Canto 7 - Chapter 1 - Verse 25
रजस्तमश्च सत्त्वेन सत्त्वं चोपशमेन च ।एतत्सर्वं गुरौ भक्त्या पुरुषो ह्यञ्जसा जयेत् ॥ २५ ॥
rajas tamaś ca sattvenasattvaṁ copaśamena caetat sarvaṁ gurau bhaktyāpuruṣo hy añjasā jayet
One must conquer the modes of passion and ignorance by developing the mode of goodness, and then one must become detached from the mode of goodness by promoting oneself to the platform of śuddha-sattva. All this can be automatically done if one engages in the service of the spiritual master with faith and devotion. In this way one can conquer the influence of the modes of nature.
Just by treating the root cause of an ailment, one can conquer all bodily pains and sufferings. Similarly, if one is devoted and faithful to the spiritual master, he can conquer the influence of sattva-guṇa, rajo-guṇa and tamo-guṇa very easily. Yogīs and jñānīs practice in many ways to conquer the senses, but the bhakta immediately attains the mercy of the Supreme Personality of Godhead through the mercy of the spiritual master. Yasya prasādād bhagavat-prasādo. If the spiritual master is favorably inclined, one naturally receives the mercy of the Supreme Lord, and by the mercy of the Supreme Lord one immediately becomes transcendental, conquering all the influences of sattva-guṇa, rajo-guṇa and tamo-guṇa within this material world. This is confirmed in Bhagavad-gītā (sa guṇān samatītyaitān brahma-bhūyāya kalpate). If one is a pure devotee acting under the directions of the guru, one easily gets the mercy of the Supreme Lord and thus becomes immediately situated on the transcendental platform. This is explained in the next verse.