A devotional song is a hymn that accompanies religious observances and rituals.
Within the Reformed tradition, church music in general was hotly debated; some Puritans objected to all ornament and sought to abolish choirs, hymns, and, inasmuch as liturgy itself was rejected, devotionals.
In Eastern and Near-Eastern religions, devotionals can function as communion prayer and meditation.
These are sung in particular rhythms which are sustained over a prolonged period to give practitioners a mystical experience.
In Hindu music, the genre arising out of the Bhakti movement (devotion), it takes forms like Bhajan, Kirtan and Aarti.