CC Madhya 9.106

tabe mahāprabhu tāṅre karāila śikṣaṇa
ei bāt kāhāṅ nā kariha prakāśana
Word for word: 
tabe — then; mahāprabhu — Śrī Caitanya Mahāprabhu; tāṅre — unto the brāhmaṇa; karāila — made; śikṣaṇa — instruction; ei bāt — this version; kāhāṅ — anywhere; — do not; kariha — do; prakāśana — revelation.
Translation: 
Śrī Caitanya Mahāprabhu then taught the brāhmaṇa very thoroughly and requested him not to disclose the fact that He was Lord Kṛṣṇa Himself.