CC Madhya 8.282
‘rasa-rāja’, ‘mahābhāva’ — dui eka rūpa
Lord Śrī Kṛṣṇa is the reservoir of all pleasure, and Śrīmatī Rādhārāṇī is the personification of ecstatic love of Godhead. These two forms had combined as one in Śrī Caitanya Mahāprabhu. This being the case, Lord Śrī Caitanya Mahāprabhu revealed His real form to Rāmānanda Rāya.
This is described as rādhā-bhāva-dyuti-suvalitaṁ naumi kṛṣṇa-svarūpam. Lord Śrī Kṛṣṇa was absorbed in the features of Śrīmatī Rādhārāṇī. This was disclosed to Rāmānanda Rāya when he saw Lord Śrī Caitanya Mahāprabhu. An advanced devotee can understand śrī-kṛṣṇa-caitanya, rādhā-kṛṣṇa nahe anya. Śrī Caitanya Mahāprabhu, being a combination of Kṛṣṇa and Rādhā, is nondifferent from Rādhā-Kṛṣṇa combined. This is explained by Svarūpa Dāmodara Gosvāmī:
ekātmānāv api bhuvi purā deha-bhedaṁ gatau tau
caitanyākhyaṁ prakaṭam adhunā tad-dvayaṁ caikyam āptaṁ
rādhā-bhāva-dyuti-suvalitaṁ naumi kṛṣṇa-svarūpam
(Cc. Ādi 1.5)
Rādhā-Kṛṣṇa is one. Rādhā-Kṛṣṇa is Kṛṣṇa and Kṛṣṇa’s pleasure potency combined. When Kṛṣṇa exhibits His pleasure potency, He appears to be two — Rādhā and Kṛṣṇa. Otherwise, Rādhā and Kṛṣṇa are one. This oneness may be perceived by advanced devotees through the grace of Śrī Caitanya Mahāprabhu. This was the case with Rāmānanda Rāya. One may aspire to attain such a position, but one should not try to imitate the mahā-bhāgavata.