Śrī Caitanya Caritamrta · Text Madhya 25.78
প্রভু কহে, — ‘বিষ্ণু’ ‘বিষ্ণু’, আমি ক্ষুদ্র জীব হীন ।
জীবে ‘বিষ্ণু’ মানি — এই অপরাধ-চিহ্ন ॥ ৭৮ ॥
prabhu kahe, — ‘viṣṇu’ ‘viṣṇu’, āmi kṣudra jīva hīna
jīve ‘viṣṇu’ māni — ei aparādha-cihna
When Prakāśānanda Sarasvatī supported himself by quoting the verse from Śrīmad-Bhāgavatam, Śrī Caitanya Mahāprabhu immediately protested by uttering the holy name of Lord Viṣṇu. The Lord then presented Himself as a most fallen living entity, and He said, “If someone accepts a fallen conditioned soul as Viṣṇu, Bhagavān, or an incarnation, he commits a great offense.”
Read Śrīla Prabhupāda's purport on Vedabase.io