Caitanya Mahaprabhu came as a hidden avatar to teach humble submission, the only path for fallen souls to realize Krishna.Listen — Srila Prabhupada Uvaca
Anantarām Śāstrījī: [chants mantras] śacīsūnu premāvalita sukharāśe mama gurau mayā labdhaṁ labdhaṁ tava pada prasādaṁ sumadhūram kṛpā pārāvāras tvamasi bhūvijñātam punar idaṁ śaraṇyaṁ tvaṁ yāce tava caraṇa sevāṁ pratidinam My spiritual master is the embodiment of unlimited loving ecstasy for the son of Śacī. I have been blessed by the nectarean mercy of your lotus feet. You are an unlimited ocean of mercy. I beg shelter and service to your lotus feet for ever.
[Prayer to Prabhupāda composed by Anantarām Śāstrījī.] namaste namaste kṛta pura dṛṣṭe namaste namaste manaṁ dadātre namamo namamo punaḥ rakṣa rakṣa prasīda prabhupāda imaṁ dakṣa dakṣa I offer my repeated obeisances to you. Kindly cast your merciful glance upon me. I offer my obeisances to beg for your attention. I offer my repeated obeisances to beg for your protection.
O Prabhupāda, please be merciful for you are supremely competent. [Prayer to Prabhupāda composed by Anantarām Śāstrījī.] Oṁ namo bhagavate vāsudevāya. Oṁ namo bhagavate vāsudevāya. Oṁ namo bhagavate vāsudevāya.
[devotees repeat] Śrīmad-Bhāgavatam, 7.9.38 [chants verse; Prabhupāda and devotees respond] [break] itthaṁ nṛ-tiryag-ṛṣi-deva-jhaṣāvatārair lokān vibhāvayasi haṁsi jagat pratīpān dharmaṁ mahā-puruṣa pāsi yugānuvṛttaṁ channaḥ kalau yad abhavas tri-yugo 'tha sa tvam [SB 7.9.38] [04:10] Puṣṭa Kṛṣṇa: Translation: "In this way, my Lord, You have appeared in different incarnations—as human beings, as animals, as a great saintly person, as demigods and as a fish and a tortoise. In this way You maintain the whole creation in different planetary systems and kill the demoniac principles in every age. My Lord, You therefore protect the principles of religion. In the Age of Kali You do not assert Yourself as the Supreme Personality of Godhead.
Therefore You are known as Tri-yuga, or the Lord who appears in three yugas." Prabhupāda: itthaṁ nṛ-tiryag-ṛṣi-deva-jhaṣāvatārair lokān vibhāvayasi haṁsi jagat pratīpān dharmaṁ mahā-puruṣa pāsi yugānuvṛttaṁ channaḥ kalau yad abhavas tri-yugo 'tha sa tvam [SB 7.9.38] So here is a very specific statement about Śrī Caitanya Mahāprabhu, His avatāra. Caitanya Mahāprabhu is the same Supreme Personality of Godhead, but He's channa. Channa means covered. Not directly, because He has appeared as a devotee.
Avatāra... Rūpa Gosvāmī has found out that He's avatāra of Kṛṣṇa. All the devotees—Sārvabhauma Bhaṭṭācārya, Rūpa Gosvāmī—and in the śāstra, and the Upaniṣad, Mahābhārata, in every... Sādhu-śāstra.
Avatāra should be confirmed by great devotees, personalities, and must be corraborated with the statement in the śāstra. So here is another statement in the Śrīmad-Bhāgavatam. The directly, it is stated in the Eleventh Canto, you know, kṛṣṇa-varṇaṁ tviṣākṛṣṇaṁ sāṅgopāṅgāstra-pārṣadam yajñaiḥ saṅkīrtanaiḥ prāyair yajanti hi sumedhasaḥ [SB 11.5.32] The Supreme Personality of Godhead, when He was being described before King Nimi by Karabhājana Muni, the different incarnation in different millenniums, yuga-dharma-pālau. [CB Ādi-khaṇḍa 1.1] Caitanya Mahāprabhu is also described by Vṛndāvana dāsa Ṭhākura, yuga-dharma-pālo.