CC Antya 19.109

mahāprabhu-nityānanda, doṅhāra dāsera dāsa
yāre kṛpā karena, tāra haya ithe viśvāsa
Word for word: 
mahāprabhu — Śrī Caitanya Mahāprabhu; nityānanda — Lord Nityānanda; doṅhāra dāsera dāsa — I am a servant of the servant of the servants of these two personalities; yāre kṛpā karena — if anyone is favored by Them; tāra haya — he certainly maintains; ithe viśvāsa — faith in all these affairs.
Translation: 
If one becomes a servant of the servants of Śrī Caitanya Mahāprabhu and Lord Nityānanda Prabhu and is favored by Them, he can believe in all these discourses.