CC Madhya 13.54

keha lakhite nāre prabhura acintya-śakti
antaraṅga-bhakta jāne, yāṅra śuddha-bhakti

keha—anyone; lakhite—see; nāre—cannot; prabhura—of Śrī Caitanya Mahāprabhu; acintya—inconceivable; śakti—power; antaraṅga—intimate; bhakta—devotee; jāne—knows; yāṅra—whose; śuddha-bhakti—pure devotional service.

Actually, no one could see the inconceivable potency of the Lord. Only the most confidential devotees, those in pure, unalloyed devotional service, could understand.