CC Antya 16.71

“tumi kṛṣṇa-nāma-mantra kailā upadeśe
mantra pāñā kā’ra āge nā kare prakāśe
Word for word: 
tumi — You; kṛṣṇa-nāma — the holy name of Kṛṣṇa; mantra — this hymn; kailā upadeśe — have instructed; mantra pāñā — getting the hymn; kā’ra āge — in front of everyone; kare prakāśe — he does not express.
Translation: 
“My Lord,” he said, “You have given him initiation into the name of Kṛṣṇa, but after receiving the mantra he will not express it in front of everyone.