The ruling on praying on the ground and on a prayer mat at the same time

Question:
May Allah reward you. The questioner, Ayn Waw from Riyadh, has a set of questions. She says: Honorable Shaykh, we are a group of female students at school. Sometimes we have only one prayer mat with us, so we spread it out lengthwise so that every two students can pray on it at the same time. However, some of our sisters disapproved of this action. What is the correct ruling on this? Are we sinful?

Answer:
If the place is pure, there is nothing wrong with praying on the ground or on the pure place. As for the prayer mat, the matter is easy; if you have it, that is good, and if you do not have it, there is no necessity for it. There is no harm in spreading it under your feet or spreading it lengthwise so that you prostrate on it. There is no harm in that. The matter is easy in this, and there is no disapproval of it. Yes.