Al-Mufaddal ibn Salih from Al-Husayn ibn Hammad, who said:
I asked Abu Abdillah عليه السلام, about a man who prostrates upon pebbles. Imam عليه السلام said: "He should raise his head until he becomes firmly settled."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 335
