From the belief system of Islam is the origins of Sufism.  Sufism is often said to be the mystical branch of Islam. 

Realizing a mystical connection with the divine or experiencing unity with God or mystical love is one of the aims of Sufism.

In Sufism the practice of chanting songs, or texts and poetry is practiced to reach this objective.  The type of music used to do this is called qawwali. 

The form of music that Qawwali is, is one of a devotional nature.  The function of this music is a spiritual function in facilitating the divine connection.  This is the central purpose of this devotional form of music of Qawwali.

Qawwali music has particular musical characteristics and fits into the category of North Indian Classical music.

A particular chanting practice is used in order to arouse the emotional and spiritual connection with God.  This chanting practice is the recitation of God’s name.  ”Zikr” is the name given to this chanting practice.  The listening practice of this devotional music is called “sama”.

Zikr and sama set the context in order to experience the emotional connection to God within Sufism.  The poetry or text is the vehicle through which the mystical love is communicated and experienced.  The poetry is set to music.

The performers aim for that of the listeners is to bring about an intensification of the text.  Through improvisation the singer shapes the structure of the music for this to occur.  The singer uses repetition of phrases, clapping and changes in tempo to intensify the emotions of the listeners.

There are two functions to the process of intensification: that of reinforcing but also in the generation of increased spiritual arousal.

The performer is acutely aware of the impact of his performance on the listeners.  As long as the song is effecting the audience, it is continued.  Once the effect of a song has stopped it will be stopped and another song will commence.

So in Sufism to facilitate the spiritual experience of mystical love, unity and connection to God, the practice of chanting is utilized.