Prohibition of Prostrating on Graves of the Ahl Al-Bayt (عليه السلام)

وَ قَرَأْتُ التَّوْقِيعَ وَ مِنْهُ نَسَخْتُ أَمَّا السُّجُودُ عَلَى الْقَبْرِ فَلَا يَجُوزُ فِي نَافِلَةٍ وَ لَا فَرِيضَةٍ وَ لَا زِيَارَةٍ 

"And he recited the letter and from his copy (it said): 'As for sajdah (prostration) upon the qabr (grave) it is NOT permissible in naafilah (salaah), fareeDah (salaah), and in ziyaarah (visitation to the grave)
Source:

1.     Al-Toosi, Tahdheeb Al-aHkaam, vol. 2, pg. 228, hadeeth # 107

Grading:

1.       Al-Majlisi said this hadeeth is Hasan Kal-SaHeeH (Hasan like a SaHeeH (hadeeth))
à Milaadh Al-Akhyaar, vol. 4, pg. 238

مُحَمَّدُ بْنُ عَلِيِّ بْنِ الْحُسَيْنِ قَالَ قَالَ رَسُولُ اللَّهِ ص لَا تَتَّخِذُوا قَبْرِي قِبْلَةً وَ لَا مَسْجِداً فَإِنَّ اللَّهَ عَزَّ وَ جَلَّ لَعَنَ الْيَهُودَ- حَيْثُ اتَّخَذُوا قُبُورَ أَنْبِيَائِهِمْ مَسَاجِدَ

"He (عليه السلام) said: The Messenger of Allaah (صلى الله عليه وآله وسلم) said: ‘Do not take my grave as a qiblah and not as a masjid*. For verily Allaah (عَزَّ وَ جَلَّ) cursed the jews because they took the graves of their prophets as masaajid (pl. masjid)’"
Source:

1.       Al-Sadooq, Man Laa YaHDuruh Al-Faqeeh, vol. 1, pg. 178, hadeeth # 532

* Masjid - Can mean a mosque, or a place where sajdah is done a lot.

وَ لَا تَتَّخِذْ شَيْئاً مِنْهَا قِبْلَةً فَإِنَّ رَسُولَ اللَّهِ ص نَهَى عَنْ ذَلِكَ وَ قَالَ لَا تَتَّخِذُوا قَبْرِي قِبْلَةً وَ لَا مَسْجِداً فَإِنَّ اللَّهَ لَعَنَ الَّذِينَ اتَّخَذُوا قُبُورَ أَنْبِيَائِهِمْ مَسَاجِدَ

"And do not take anything from it as a qiblah. For verily the Messenger of Allaah (صلى الله عليه وآله وسلم) prohibited that. And He (صلى الله عليه وآله وسلم) said: 'Do not take my grave as a qiblah and not as a masjid. For Verily Allaah (عَزَّ وَ جَلَّ) cursed those who took the graves of their Prophets as masaajid (pl. masjid)"
Source:

1.       Al-Sadooq, `ilal al-Sharaa’i`, vol. 2, pg. 358, hadeeth # 1

Here is what one of our greatest classical scholars, Al-Toosi has said in his Fiqh book:

و لا يجوز السّجود إلّا على الأرض أو ما أنبتته الأرض، إلّا ما أكل أو لبس، و لا يجوز السّجود على القبر

“And sajdah is not allowed except upon the earth or what grows (from) the earth, except what (can be) eaten or worn, and sajdah is not allowed upon the grave”
Source:

1.       Al-Toosi, Al-Nihaayah fee Mujarrid Al-Fiqh wa Al-Fataawa, pg. 101

و كذلك لا يجوز السجود على القبر
“And as that likes it is NOT permissible to do sajdah upon the graves”
Source:

1.     Al-Jazeeree, Al-Fiqh `ala Al-Madhaahib Al-Arba`ah wa madhhab Ahl Al-Bayt, vol. 1, “Under the belief of the Ahl Al-Bayt (عليه السلام) section, pg. 338