Musannaf Ibn Abi Shaybah

A female servant of Hazrat Abu Hazim says that I was among the people of Suffa. We had ropes; when we became tired in prayer or felt sleepy, we would hold onto those ropes, and we also had mats on which we would stand to protect ourselves from the hardness of the ground. Once, Hazrat Abu Bakr came and said, "Cut these ropes and pray on the ground."