CC Madhya 23.13
sei premā ‘prayojana’ sarvānanda-dhāma
“When that ecstatic emotional stage intensifies, it is called love of Godhead. Such love is life’s ultimate goal and the reservoir of all pleasure.
Śrīla Bhaktivinoda Ṭhākura summarizes this growth of love of Godhead as a gradual process. A person becomes interested in devotional service by some good fortune. Eventually he becomes interested in pure devotional service without material contamination. At that point, a person wants to associate with devotees. As a result of this association, he becomes more and more interested in discharging devotional service and hearing and chanting. The more one is interested in hearing and chanting, the more he is purified of material contamination. Liberation from material contamination is called anartha-nivṛtti, indicating a diminishing of all unwanted things. This is the test of development in devotional service. If one actually develops the devotional attitude, he must be freed from the material contamination of illicit sex, intoxication, gambling and meat-eating. These are the preliminary symptoms. When one is freed from all material contamination, his firm faith in devotional service awakens. When firm faith develops, a taste arises, and by that taste one becomes attached to devotional service. When this attachment intensifies, the seed of love of Kṛṣṇa fructifies. This position is called prīti or rati (affection) or bhāva (emotion). When rati intensifies, it is called love of Godhead. This love of Godhead is actually life’s highest perfection and the reservoir of all pleasure.
Thus devotional life is divided into two stages — sādhana-bhakti and bhāva-bhakti. Sādhana-bhakti refers to the development of devotional service through the regulative principles. The basic principle for the execution of devotional service is faith. Above that, there is association with devotees, and after that there is initiation by a bona fide spiritual master. After initiation, when one follows the regulative principles of devotional service, one becomes freed from all unwanted things. In this way one becomes firmly fixed and gradually develops a taste for devotional service. The more the taste grows, the more one desires to render service to the Lord. In this way one becomes attached to a particular mellow in the Lord’s service — śānta, dāsya, sakhya, vātsalya or madhura. As a result of such attachment, bhāva develops. Bhāva-bhakti is the platform of purified goodness. By such purified goodness, one’s heart melts in devotional service. Bhāva-bhakti is the first seed of love of Godhead. This emotional stage is there before one attains pure love. When that emotional stage intensifies, it is called prema-bhakti, or transcendental love of Godhead. This gradual process is also described in the following two verses, which are found in the Bhakti-rasāmṛta-sindhu (1.4.15-16).