They execute this ninefold devotional service in the stage of sādhana, or practice, and feel deep satisfaction in the perfected, or siddha, stage. They become saturated with the transcendental spiritual mellows of servitorship, friendship, and so on, from which they derive divine ecstasy. Lord Kṛṣṇa grants genuine transcendental understanding, buddhi-yoga, to those devotees who experience spiritual satisfaction and divine bliss through constant devotional service; gradually their specific devotional attitude increases to the point where they can relish pure love of God.
In the stage of bhāva, or spontaneous devotional service in ecstasy, there is a direct transcendental exchange of mellows between Lord Kṛṣṇa and His pure devotee. The Supreme Lord Himself gives His devotee buddhi-yoga, or spiritual intelligence, and the devotee, acting with that intelligence, serves the Lord until he gradually approaches the Lord's supreme abode. Such a devotee can never be affected by ignorance.