CC Ādi 13.39
premāvasthā śikhāilā āsvādana-cchale
A person who is advanced in Kṛṣṇa consciousness always feels separation from Kṛṣṇa because such a feeling of separation excels the feeling of meeting Kṛṣṇa. Śrī Caitanya Mahāprabhu, in His last twelve years of existence within this world at Jagannātha Purī, taught the people of the world how, with a feeling of separation, one can develop His dormant love of Kṛṣṇa. Such feelings of separation or meeting with Kṛṣṇa are different stages of love of Godhead. These feelings develop in time when a person seriously engages in devotional service. The highest stage is called prema-bhakti, but this stage is attained by executing sādhana-bhakti. One should not try to elevate himself artificially to the stage of prema-bhakti without seriously following the regulative principles of sādhana-bhakti. Prema-bhakti is the stage of relishing, whereas sādhana-bhakti is the stage of improving in devotional service. Śrī Caitanya Mahāprabhu taught this cult of devotional service in full detail by practical application in His own life. It is said, therefore, āpani ācari’ bhakti śikhāimu sabāre. Śrī Caitanya Mahāprabhu is Kṛṣṇa Himself, and in the role of a kṛṣṇa-bhakta, a devotee of Kṛṣṇa, He instructed the entire world how one can execute devotional service and thus go back home, back to Godhead, in due course of time.