Sunan Abi Dawud 3225
سنن أبي داود#3225SahihNarrated Jabir:I heard the Prophet (ﷺ) forbid to sit on the grave, to plaster it with gypsum, and to build any structure over it
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Shuaib Al ArnautHasan Sahih
Zubair Ali ZaiSahih Muslim (970)
In-book reference: 21:137