Prayer is not valid on the carpet since prostration - based on the jurisprudence of the Ahlulbait (peace be upon them) - must be on natural earth like soil, stones, rocks and similar materials, or on what grows on earth provided that it is not consumed for food or worn as clothing. It is narrated - in both Sunni and Shia books of traditions - that the Prophet (peace be upon him and his holy progeny) said: "Earth is made for me as a place of prostration and a purifying agent". Some Sunni books of narrations state that the Prophet (peace be upon him and his progeny) used to have a piece of cloth in which he put soil in it and he opened it and prostrated on the soil.
