Ali bin Jafar said it was asked to Abul Hasan Al Musa Kazim عليه السلام that what about building structure over a grave and sitting on it?
So Imam Musa Al Kazim عليه السلام replied:
لا يصلح البناء عليه ولا الجلوس ولا تجصيصه ولا تطيينه.
It is not valid to build a structure over a grave, sitting on it, making it paved and plastering it.
[Al istibsar 1/217, Tahdhib Al Ahkam 1/461]
Imam Jafar as Sadiq رحمہ اللہ said:
عن ابي عبد الله عليه السلام قال: نهى رسول الله صلى الله عليه وسلم ان يصلى على قبر او يقعد عليه او يبنى عليه
Rasool صلی اللہ علیہ وسلم forbade to pray on the grave or sitting on it or building the structure over it.
[Tahdhib Al Ahkam 1/461, Al Istibsar 1/482]
Praying on the grave means, to pray facing the grave, it doesn't mean the funeral prayer because Imam Jafar sadiq رحمہ اللہ said, if one could pray the janazah/funeral prayer then pray the janazah/funeral after tadfeen.
[Al Istibsar 1/482]
Imam Jafar sadiq رحمہ اللہ said:
لا تبنوا على القبور ولا تصورو سقوف البيوت فان رسول الله صلى عليه وسلم كره ذلك
Do not build structures over thr graves nor illustrate your roofs with paintings. Without any doubt Rasool صلی اللہ علیہ وسلم disliked these.
[Tahdhib al Ahkam 1/346]
Imam Jafar Sadiq رحمہ اللہ said
ان النبى صلى الله عليه وسلم نهى ال يزاد على القبر تراب لم يخرج منه
Rasool صلی اللہ علیہ وسلم forbade to put the excess the soil on the grave which didn't come out of the same grave.
[Tahdhib Al Ahkam 1/360-361, Furu al Kafi- Book of Funerals 3/202]
