CC Madhya-lila 22.066 - BRS 1.2.17
Sri Caitanya-caritamrta
CC Madhya-lila
CC Madhya 22.66, Translation and Purport:
“"One who is expert in logic and in understanding the revealed scriptures, and who always has firm conviction and deep faith that is not blind, is to be considered a topmost devotee in devotional service."
This verse appears in the Bhakti-rasāmṛta-sindhu (1.2.17), by Śrīla Rūpa Gosvāmī.