Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 15
गिरयो वर्षधाराभिर्हन्यमाना न विव्यथु: ।अभिभूयमाना व्यसनैर्यथाधोक्षजचेतस: ॥ १५ ॥
girayo varṣa-dhārābhirhanyamānā na vivyathuḥabhibhūyamānā vyasanairyathādhokṣaja-cetasaḥ
Just as devotees whose minds are absorbed in the Personality of Godhead remain peaceful even when attacked by all sorts of dangers, the mountains in the rainy season were not at all disturbed by the repeated striking of the rain-bearing clouds.
When splashed by torrents of rain, the mountains are not shaken; rather, they are cleansed of dirt and become resplendent and beautiful. Similarly, an advanced devotee of the Supreme Lord is not shaken from his devotional program by disturbing conditions, which instead cleanse his heart of the dust of attachment to this world. Thus the devotee becomes beautiful and resplendent by tolerating difficult conditions. In fact, a devotee accepts all reverses in life as the mercy of Lord Kṛṣṇa, realizing that all suffering is due to the sufferer’s own previous misdeeds.