(Sri Caitanya Mahaprabhu, 19th century oil painting, Bengal)
"Kṛṣṇa was always amazed by Rādhārāṇī's love. 'How does Rādhārāṇī give Me such pleasure?' He would ask. In order to study Rādhārāṇī, Kṛṣṇa lived in Her role and tried to understand Himself. This is the secret of Lord Caitanya's incarnation. Caitanya Mahāprabhu is Kṛṣṇa, but He has taken the mood and role of Rādhārāṇī to show us how to love Kṛṣṇa. Thus He is addressed, 'I offer my respectful obeisances unto the Supreme Lord, who is absorbed in Rādhārāṇī's thoughts.'
This brings up the question of who Śrīmatī Rādhārāṇī is and what Rādhā-Kṛṣṇa is. Actually Rādhā-Kṛṣṇa is the exchange of love. This is not ordinary love; Kṛṣṇa has immense potencies, of which three are principal: the internal, the external and the marginal potencies. In the internal potency there are three divisions: saṁvit, hlādinī and sandhinī. The hlādinī potency is the pleasure potency. All living entities have this pleasure-seeking potency, for all beings are trying to have pleasure. This is the very nature of the living entity. At present we are trying to enjoy our pleasure potency by means of the body in this material condition. By bodily contact we are attempting to derive pleasure from material sense objects. We should not think, however, that Kṛṣṇa, who is always spiritual, tries to seek pleasure on this material plane like us. In the Bhagavad-gītā Kṛṣṇa describes the material universe as a nonpermanent place full of miseries. Why, then, would He seek pleasure in the material form? He is the Supersoul, the supreme spirit, and His pleasure is beyond the material conception.
In order to learn how Kṛṣṇa's pleasure can be obtained, we must read the Tenth Canto of Śrīmad-Bhāgavatam, in which Kṛṣṇa's pleasure potency is displayed in His pastimes with Rādhārāṇī and the damsels of Vraja. Unfortunately, unintelligent people turn at once to the sports of Kṛṣṇa in the Daśama-skandha, the Tenth Canto. Kṛṣṇa's embracing Rādhārāṇī or His dancing with the cowherd girls in the rāsa dance are generally not understood by ordinary men because they consider these pastimes in the light of mundane lust. They incorrectly think that Kṛṣṇa is like themselves and that He embraces the gopīs just as an ordinary man embraces a young girl. Some people thus become interested in Kṛṣṇa because they think that His religion allows indulgence in sex. This is not kṛṣṇa-bhakti, love of Kṛṣṇa, but prākṛta-sahajiya— materialistic lust.
In order to avoid such errors, we should understand what Rādhā-Kṛṣṇa actually is. Rādhā and Kṛṣṇa display Their pastimes through Kṛṣṇa's internal energy. The pleasure potency of Kṛṣṇa's internal energy is a most difficult subject matter, and unless one understands what Kṛṣṇa is, one cannot understand it. Kṛṣṇa does not take any pleasure in this material world, but He has a pleasure potency. Because we are part and parcel of Kṛṣṇa, the pleasure potency is within us also, but we are trying to exhibit that pleasure potency in matter. Kṛṣṇa, however, does not make such a vain attempt. The object of Kṛṣṇa's pleasure potency is Rādhārāṇī; Kṛṣṇa exhibits His potency, or energy as Rādhārāṇī and then engages in loving affairs with Her. In other words, Kṛṣṇa does not take pleasure in this external energy but exhibits His internal energy, His pleasure potency, as Rādhārāṇī. Thus Kṛṣṇa manifests Himself as Rādhārāṇī in order to exhibit His internal pleasure potency. Of the many extensions, expansions and incarnations of the Lord, this pleasure potency is the foremost and chief.
It is not that Rādhārāṇī is separate from Kṛṣṇa. Rādhārāṇī is also Kṛṣṇa, for there is no difference between the energy and the energetic. Without energy, there is no meaning to the energetic, and without the energetic, there is no energy. Similarly, without Rādhā there is no meaning to Kṛṣṇa, and without Kṛṣṇa there is no meaning to Rādhā. Because of this, the Vaiṣṇava philosophy first of all pays obeisances to and worships the internal pleasure potency of the Supreme Lord. Thus the Lord and His potency are always referred to as Rādhā-Kṛṣṇa. Similarly, those who worship the name of Nārāyaṇa first of all utter the name of Lakṣmī, as Lakṣmī-Nārāyaṇa. Similarly, those who worship Lord Rāma first of all utter the name of Sītā. In any case-Sītā-Rāma, Rādhā-Kṛṣṇa, Lakṣmī-Nārāyaṇa-the potency always comes first.
Rādhā and Kṛṣṇa are one, and when Kṛṣṇa desires to enjoy pleasure, He manifests Himself as Rādhārāṇī. The spiritual exchange of love between Rādhā and Kṛṣṇa is the actual display of the internal pleasure potency of Kṛṣṇa. Although we speak of 'when' Kṛṣṇa desires, just when He did desire we cannot say. We only speak in this way because in conditioned life we take it that everything has a beginning; however, in the absolute, or spiritual, life there is neither beginning nor end. Yet in order to understand that Rādhā and Kṛṣṇa are one and that They also become divided, the question 'When?' automatically comes to mind. When Kṛṣṇa desired to enjoy His pleasure potency, He manifested Himself in the separate form of Rādhārāṇī, and when He wanted to understand Himself through the agency of Rādhā, He united with Rādhārāṇī, and that unification is called Lord Caitanya.
Why did Kṛṣṇa assume the form of Caitanya Mahāprabhu? It is explained that Kṛṣṇa desired to know the glory of Rādhā's love. 'Why is She so much in love with Me?' Kṛṣṇa asked. 'What is My special qualification that attracts Her so? And what is the actual way in which She loves Me?' It seems strange that Kṛṣṇa, as the Supreme, should be attracted by anyone's love. We search after the love of a woman or a man because we are imperfect and lack something. The love of a woman, that potency and pleasure, is absent in man, and therefore a man wants a woman, but this is not the case with Kṛṣṇa, who is full in Himself. Thus Kṛṣṇa expressed surprise: 'Why am I attracted by Rādhārāṇī? And when Rādhārāṇī feels My love, what is She actually feeling?' In order to taste the essence of that loving affair, Kṛṣṇa appeared just as the moon appears on the horizon of the sea. Just as the moon was produced by the churning of the sea, by the churning of spiritual love affairs the moon of Caitanya Mahāprabhu appeared. Indeed, Lord Caitanya's complexion was golden, just like the moon. Although this is figurative language, it conveys the meaning behind the appearance of Caitanya Mahāprabhu."