قَالَ أَبُو عَبْدِ اللَّهِ ع الطِّينُ حَرَامٌ كُلُّهُ كَلَحْمِ الْخِنْزِيرِ وَ مَنْ أَكَلَهُ ثُمَّ مَاتَ فِيهِ لَمْ أُصَلِّ عَلَيْهِ إِلَّا طِينَ الْقَبْرِ[2] فَإِنَّ فِيهِ شِفَاءً مِنْ كُلِّ دَاءٍ وَ مَنْ أَكَلَهُ لِشَهْوَةٍ لَمْ يَكُنْ لَهُ فِيهِ شِفَاءٌ.
’Eating clay is unlawful in its entirety, like the flesh of pork. If one eats it and dies, I will not perform Salat (prayer) for him except the clay from the grave (of al-Husayn (a.s.) ) in which there is cure for all kinds of illnesses but if one eats it because of strong desire, then there is no cure in it.’”