Dhikr is what fills the space between the fixed prayers: short formulas repeated on beads, on the breath, or aloud in a gathering — subhanallah, alhamdulillah, allahu akbar, thirty-three each after prayer is the common pattern. Sufi orders developed it furthest, into communal sessions with breath control, movement, and sometimes music, and this is precisely where reformist critics have objected. The Quranic warrant is direct and often quoted: hearts find rest in the remembrance of God.