CC Ādi 8.9
চৈতন্য না মানিলে তৈছে দৈত্য তারে জানি ॥ ৯ ॥
caitanya nā mānile taiche daitya tāre jāni
One who does not accept Kṛṣṇa as the Supreme Personality of Godhead is certainly a demon. Similarly, anyone who does not accept Śrī Caitanya Mahāprabhu as Kṛṣṇa, the same Supreme Lord, is also to be considered a demon.
Formerly there were kings like Jarāsandha who strictly followed the Vedic rituals, acted as charitable, competent kṣatriyas, possessed all kṣatriya qualities and were even obedient to the brahminical culture but who did not accept Kṛṣṇa as the Supreme Personality of Godhead. Jarāsandha attacked Kṛṣṇa many times, and each time, of course, he was defeated. Like Jarāsandha, any man who performs Vedic rituals but does not accept Kṛṣṇa as the Supreme Personality of Godhead must be considered an asura, or demon. Similarly, one who does not accept Śrī Caitanya Mahāprabhu as Kṛṣṇa Himself is also a demon. This is the conclusion of authoritative scriptures. Therefore, both so-called devotion to Gaurasundara without devotional service to Kṛṣṇa and so-called kṛṣṇa-bhakti without devotional service to Gaurasundara are nondevotional activities. If one wants to be successful on the path of Kṛṣṇa consciousness, he must be thoroughly conscious of the personality of Gaurasundara as well as the personality of Kṛṣṇa. Knowing the personality of Gaurasundara means knowing the personalities of śrī-kṛṣṇa-caitanya prabhu-nityānanda śrī-advaita gadādhara śrīvāsādi-gaura-bhakta-vṛnda. The author of Śrī Caitanya-caritāmṛta, pursuant to the authorities, stresses this principle for perfection in Kṛṣṇa consciousness.