Prayer is an integral part of all the world's religions. Prayer takes many forms. There are inner and outer forms of prayer. There are silent prayers and prayers that are spoken, chanted, or sung aloud. There are fixed, formal prayers, and spontaneous prayers, inspired by the heart. Behind all real prayer is the sincere heart, longing for God, longing for connection to the Divine.
— James Fadiman, Robert Frager, Essential Sufism by James Fadiman, editor, Robert Frager, editor