Caitanya Mahāprabhu informs us that in every country and in every scripture there is some hint of love of Godhead. But no one knows what love of Godhead actually is. The Vedic scriptures, however, are different in that they can direct the individual in the proper way to love God. Other scriptures do not give information on how one can love God, nor do they actually define or describe what or who the Godhead actually is. Although they officially promote love of Godhead, they have no idea how to execute it. But Caitanya Mahāprabhu gives a practical demonstration of how to love God in a conjugal relationship. Taking the part of Śrīmatī Rādhārāṇī, Caitanya Mahāprabhu tried to love Kṛṣṇa as Rādhārāṇī loved Him. 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 the author writes in the fifth verse, “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—but 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: samvit, hlādinī and sandhinī. The hlādinī potency is Kṛṣṇa's 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 the material condition. By bodily contact we are attempting to derive pleasure from material sense objects. But we should not entertain the nonsensical idea that Kṛṣṇa, who is always spiritual, also tries to seek pleasure on this material plane. In the Bhagavad-gītā Kṛṣṇa describes the material universe as a nonpermanent place full of miseries. Why, then, would He seek pleasure in matter? He is the Supersoul, the supreme spirit, and His pleasure is beyond the material conception.
To learn how Kṛṣṇa enjoys pleasure, we must study the first nine cantos of Śrīmad-Bhāgavatam, and then we should study the Tenth Canto, 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 foolishly 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-sahajiyā—materialistic lust.
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 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 and then enjoys with Her. Thus Kṛṣṇa manifests Himself as Rādhārāṇī in order to enjoy 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 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 Kṛṣṇa's internal pleasure potency. 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 spiritual life everything is absolute, and so 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. This is all explained by Śrīla Kṛṣṇadāsa Kavirāja in the fifth verse of the Caitanya-caritāmṛta.