After receiving initiation at Gaya from Srila Iswara Puri, Sri Gaurasundar, the son of Mother Sachi, returned to Nadiya with a happy heart. One day, Vishwambhar gave transcendental knowledge to some pure brahmin boys of Nabadwip who were his students.
Lord Gaura Hari said: pana eka satya vastu - krsnera carana sei vidya - yathe hari-bhaktira laksana
You should study only the one truth - Krishna's feet. One who knows that truth has the ornament of devotion for the Lord. (Text 11)
The sastras describe that anything other than this is ignorance. Do not study anything other than devotion to Sri Sri Radha-Krishna! (Text 12)
Persons intoxicated with pride in their learning, wealth, and birth do not attain Krishna. By devotional service one easily attains Krishna, the Lord of the Yadus. (Text 13)
Krishna is conquered by the nectar of devotional service. To prove this I quote these words from the sastras: (Text 14)
Where was the hunter Dharma's piety, Dhruva's maturity, and Gajendra's knowledge? Where was Kubja's beauty? Where was Sudama's wealth? Where was Vidura's noble birth? Where was Ugrasena's chivalrous strength? Lord Madhava is pleased only by devotional service and not by material qualifications. (Text 15: quoting Rupa Goswami's Padyavali, text 8).
--Adapted from Srila Lochan Das Thakur's Caitanya-mangala, Madhya 1.11-15