Viṣaya and āśraya are two very significant words relating to the reciprocation between Kṛṣṇa and His devotee. The devotee is called the āśraya, and his beloved, Kṛṣṇa, is the viṣaya. Different ingredients are involved in the exchange of love between the āśraya and viṣaya, which are known as vibhāva, anubhāva, sāttvika and vyabhicārī. Vibhāva is divided into the two categories ālambana and uddīpana. Ālambana may be further divided into āśraya and viṣaya. In the loving affairs of Rādhā and Kṛṣṇa, Rādhārāṇī is the āśraya feature and Kṛṣṇa the viṣaya. The transcendental consciousness of the Lord tells Him, "I am Kṛṣṇa, and I experience pleasure as the viṣaya. The pleasure enjoyed by Rādhārāṇī, the āśraya, is many times greater than the pleasure I feel." Therefore, to feel the pleasure of the āśraya category, Lord Kṛṣṇa appeared as Śrī Caitanya Mahāprabhu.
(Sri Caitanya Caritamrta------1:4:135------purport).

Kṛṣṇa's attractiveness is wonderful and unlimited. No one can know the end of it. Śrīmatī Rādhārāṇī alone can relish such extensiveness from Her position in the āśraya category. The mirror of Śrīmatī Rādhārāṇī’s transcendental love is perfectly clear, yet it appears clearer and clearest in the transcendental method of understanding Kṛṣṇa. In the mirror of Rādhārāṇī’s heart, the transcendental features of Kṛṣṇa appear increasingly new and fresh. In other words, the attraction of Kṛṣṇa increases in proportion to the understanding of Śrīmatī Rādhārāṇī. Each tries to supersede the other. Neither wants to be defeated in increasing the intensity of love. Desiring to understand Rādhārāṇī’s attitude of increasing love, Lord Kṛṣṇa appeared as Śrī Caitanya Mahāprabhu.
(Sri Caitanya Caritamrta------1:4:145------purport).