Stages of bhakti (sadhana bhakti, bhao bhakti, prema bhakti)
There are three main stages of bhakti:
(the practice of devotion)
Sadhana bhakti means the actual practice of devotion when you do roop dhyan and kirtan. You have to make the effort to practice bhakti in this way. Practicing sadhana bhakti will gradually purify your heart. When you reach a certain degree of heart purification, you will begin to enter bhao bhakti.
(natural devotional consciousness)
Bhao bhakti is a natural state of devotional consciousness when the feeling of affinity for Radha Krishna remains in the heart all the time. When a devotee practices sadhana bhakti correctly, their heart will purify and they will enter the stage of bhao bhakti. Whereas sadhana bhakti means 'the practice of devotion', where the devotee tries to attach their mind to Radha and Krishna, bhao bhakti is a natural feeling of affection and affinity for Radha Krishna that stays in the heart all the time. In other words, sadhana bhakti is practiced, and bhao bhakti is a natural state into which the devotee evolves. The bhao (devotional feelings) may be stronger during devotional meditation, and may rise and fall from day to day with the coming and going of good and bad sanskars, but it remains in the heart all the time. Sometimes, the bhao can be quite strong and the devotee will feel a thrill in his heart and shed tears of love and longing. These are some of the signs of bhao bhakti.
To enter into bhao bhakti, two things are required: the correct practice of sadhana bhakti, and the Grace of a Saint. The Grace of the Saint helps to purify the mind and awaken the dormant devotional affinity that lies in the devotee's heart. Bhao bhakti continues to evolve in the heart of the devotee until the heart is fully purified. When the heart is completely purified, the devotee is qualified to receive prema bhakti.
(the ultimate Divine Bliss)
Prema bhakti is received through the Grace of God and Guru into a fully purified heart. This is the ultimate goal of devotion. Having received prema bhakti, the soul has attained the most personal Divine power of God and the ultimate Bliss of Radha Krishna.