Chapter on the Virtue of Mosques and Prayer Within Them, and the Virtue of Congregational Prayer and Its Rulings

Sa’ad ibn Abdillah from Harun ibn Muslim from Mas‘adah ibn Sadaqah al-Ruba‘i from Imam Ja’far ibn Muhammad عليه السلام, peace be upon him, who said: Imam al-Sadiq عليه السلام was asked: “Is it permissible for a place that was a refuse area to be made into a mosque?” Imam عليه السلام said: “If earth is thrown over it to cover it and to cut off its odor, then there is no problem. And that is because earth is purifying, and with it the Sunnah has proceeded.”