So Kṛṣṇa has millions of forms, as Viṣṇu, Nārāyaṇa and other also. Advaitam acyutam anādim ananta-rūpam (Bs. 5.33). Ananta-rūpam. Ādyaṁ purāṇa-puruṣaṁ nava-yauvanaṁ ca. So viṣṇur ārādhyate panthā nānyat tat-toṣa-kāraṇam. There is no other alternative to please Him. Therefore varṇāśrama-dharma is very important. That is the beginning of perfect human civilization.
But we have lost everything. Therefore Caitanya Mahāprabhu... He's also Viṣṇu, Kṛṣṇa Himself. Just to give relief to these rotten or forgotten conditioned souls of this age, Kali-yuga, He has given this one mantra, which is called mahā-mantra. What is that?