Antaḥ kṛṣṇa refers to one who is always thinking of Kṛṣṇa. This attitude is a predominant feature of Śrīmatī Rādhārāṇī. Even though many devotees always think of Kṛṣṇa, none can surpass the gopīs, among whom Rādhārāṇī is the leader in thinking of Kṛṣṇa. Rādhārāṇī’s Kṛṣṇa consciousness surpasses that of all other devotees. Lord Caitanya accepted the position of Śrīmatī Rādhārāṇī to understand Kṛṣṇa; therefore He was always thinking of Kṛṣṇa in the same way as Rādhārāṇī. By thinking of Lord Kṛṣṇa, He always overlapped Kṛṣṇa.
(Sri Caitanya Caritamrta------1:3:81-------purport).

In the Bhagavad-gītā Kṛṣṇa has taught the philosophy of surrender to the Supreme Personality of Godhead. One who has surrendered to the Supreme can make further progress by learning to love Him. Therefore the Kṛṣṇa consciousness movement propagated by Lord Caitanya is especially meant for those who are cognizant of the presence of the Supreme Godhead, the ultimate controller of everything. His mission is to teach people how to dovetail themselves into engagements of transcendental loving service. He is Kṛṣṇa teaching His own service from the position of a devotee. The Lord’s acceptance of the role of a devotee in the eternal form of Lord Śrī Caitanya Mahāprabhu is another of the Lord’s wonderful features. A conditioned soul cannot reach the absolute Personality of Godhead by his imperfect endeavor, and therefore it is wonderful that Lord Śrī Kṛṣṇa, in the form of Lord Gaurāṅga, has made it easy for everyone to approach Him. Svarūpa Dāmodara Gosvāmī has described Lord Caitanya as Kṛṣṇa Himself with the attitude of Rādhārāṇī, or a combination of Rādhā and Kṛṣṇa. The intention of Lord Caitanya is to taste Kṛṣṇa’s sweetness in transcendental love. He does not care to think of Himself as Kṛṣṇa, because He wants the position of Rādhārāṇī. We should remember this.
(Sri Caitanya Caritamrta------1:4:41-------purport).

Svarūpa Dāmodara has been identified as Lalitā-devī, the second expansion of Rādhārāṇī. However, text 160 of Kavi-karṇapūra’s authoritative Gaura-gaṇoddeśa-dīpikā describes Svarūpa Dāmodara as the same Viśākhā-devī who serves the Lord in Goloka Vṛndāvana. Therefore it is to be understood that Śrī Svarūpa Dāmodara is a direct expansion of Rādhārāṇī who helps the Lord experience the attitude of Rādhārāṇī.
(Sri Caitanya Caritamrta------1:4:105-------purport).

The heart of Lord Caitanya is the image of Śrī Rādhikā’s emotions. Thus feelings of pleasure and pain arise constantly therein.Lord Caitanya’s heart was full of the feelings of Śrīmatī Rādhārāṇī, and His appearance resembled Hers. Svarūpa Dāmodara has explained His attitude as rādhā-bhāva-mūrti, the attitude of Rādhārāṇī. One who engages in sense gratification on the material platform can hardly understand rādhā-bhāva, but one who is freed from the demands of sense gratification can understand it. Rādhā-bhāva must be understood from the Gosvāmīs, those who are actually controllers of the senses. From such authorized sources it is to be known that the attitude of Śrīmatī Rādhārāṇī is the highest perfection of conjugal love, which is the highest of the five transcendental mellows, and it is the complete perfection of love of Kṛṣṇa.
(Sri Caitanya Caritamrta------1:4:106-------translation and 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).

Of all these devotees, the gopīs are recognized as superior because they do not know anything other than satisfying Kṛṣṇa. Nor do the gopīs expect any return from Kṛṣṇa. Indeed, sometimes Kṛṣṇa puts them into extreme suffering by separating Himself from them. Nonetheless, they cannot forget Kṛṣṇa. When Kṛṣṇa left Vṛndāvana for Mathurā, the gopīs became most dejected and spent the rest of their lives simply crying in separation from Kṛṣṇa. This means that in one sense they were never actually separated from Kṛṣṇa. There is no difference between thinking of Kṛṣṇa and associating with Him. Rather, vipralambha-sevā, thinking of Kṛṣṇa in separation, as Śrī Caitanya Mahāprabhu did, is far better than serving Kṛṣṇa directly. Thus of all the devotees who have developed unalloyed devotional love for Kṛṣṇa, the gopīs are most exalted, and out of all these exalted gopīs, Śrīmatī Rādhārāṇī is the highest. No one can excel the devotional service of Śrīmatī Rādhārāṇī. Indeed, even Kṛṣṇa cannot understand the attitude of Śrīmatī Rādhārāṇī; therefore He took Her position and appeared as Śrī Caitanya Mahāprabhu, just to understand Her transcendental feelings.
(NECTAR OF INSTRUCTION).