Ali ibn Al-Husayn, from Muhammad ibn Al-Husayn ibn Abi Al-Khattab, from Ali ibn Asbat, from Ali ibn Ja'far, who said: I asked Abu Al-Hasan Musa عليه السلام, about building over the grave, sitting on it, whether it is permissible. Imam عليه السلام said: "It is not permissible to build over it, nor to sit on it, nor to plaster it with gypsum, nor to coat it with clay."