SB 11.24.28

evam anvīkṣamāṇasya
 kathaṁ vaikalpiko bhramaḥ
manaso hṛdi tiṣṭheta
 vyomnīvārkodaye tamaḥ
Word for word: 
evam — in this way; anvīkṣamāṇasya — of one who is carefully examining; katham — how; vaikalpikaḥ — based on duality; bhramaḥ — illusion; manasaḥ — of his mind; hṛdi — in the heart; tiṣṭheta — can remain; vyomni — in the sky; iva — just as; arka — of the sun; udaye — upon the rising; tamaḥ — darkness.
Translation: 
Just as the rising sun removes the darkness of the sky, similarly, this scientific knowledge of cosmic annihilation removes all illusory duality from the mind of a serious student. Even if illusion somehow enters his heart, it cannot remain there.
Purport: 

Just as the brilliant sun removes all darkness from the sky, a clear understanding of the knowledge spoken by Lord Kṛṣṇa to Uddhava removes all ignorance concocted by the material mind. One will then no longer accept the material body as the self. Even if such illusion temporarily manifests within one’s consciousness, it will be driven away by the resurgence of one’s spiritual knowledge.