It is a sad state of affairs that errant Muslims have raised graves, mounted shrines over them, and exalted the dead as was the practise of the pagans before the Call to Islam.
Today, Muslims have built huge shrines over the graves of some of the Ahlel Bayt, Sahabah, the righteous people, and others.
This has led to the inevitable result of mimicking pagans who worship the dead, either directly or indirectly.
There is therefore a necessity to raze to the ground these pagan shrines and to level the graves, as was the Sunnah.
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“Islam forbids erecting structures over graves, and commands that any such structures should be knocked down. But it is permitted to put a marker on the grave so that the family and friends of the deceased will know where it is (and nothing more than this). However, this marker should not be a structure or anything else that is not allowed in sharee’ah.”
With regard to the prohibition on erecting structures over graves, it was narrated that Jabir said:
“The Messenger of Allah forbade plastering over #graves, sitting on them and erecting #structures over them.” (Sahih Muslim, 970)
Al-Shawkani said:
“The phrase ‘erecting structures over them’ indicates that it is Haram to build anything over a grave.”
Al-Shafi’i said:
“I saw the imams in Makkah ordering that what had been built (over graves) was to be knocked down.”
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“With regard to the command to knock down structures that have been built over graves, that is proven in the Sunnah.”
It was narrated that Abu’l-Hayaaj al-Asadi said: Ali ibn Abi Talib said to me: “Shall I not send you on the same mission as the Messenger of Allah sent me? Do not leave any statue without erasing it, and do not leave any raised grave without leveling it.” (Sahih Muslim, 969).
Al-Shawkani said:
“The words ‘do not leave any raised grave without leveling it’ means that the Sunnah is that a grave should not be made very high, and there should be no differentiation between those who were virtuous and those who were not virtuous.”
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“Making a grave higher than the amount that is permitted is Haram…The making graves high that is mentioned in the Hadith especially includes the domes and shrines that are built over graves, and the taking of graves as places of worship. The Prophet cursed those who do that (refer to Nayl al-Awtaar, 4/130).”
All of these pagan shrines should be torn down and removed. Instead, all of the dead should have flat and level graves equal to everyone else. This is the faith of Islam. For the one who cannot accept this, he has deviated away from the path of the Hanif (i.e. the monotheists) and inclined himself towards the Mushriks.
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Shi'a promote grave worship, following shi'a websites are proof of veneration of graves as places of worship
The Great Merits of Imam Husain’s (A.S.) Ziyarat
https://www.imamreza.net/old/eng/imamreza.php?id=5912
Merit of visiting the grave of Imam Husayn (a.s.)