The Messenger of Allah ﷺ said, "Do not sit on graves."
أخبرنا محمد بن عبد الله بن عبد الحكم عن شعيب قال حدثنا الليث قال حدثنا خالد عن ابن أبي هلال عن أبي بكر بن حزم عن النضر بن عبد الله السلمي
عن رسول الله ﷺ قال لا تقعدوا على القبور
No references are available.
Its chain of transmission, hasan. Ahmad narrated it from the hadith of Saeed bin Abu Hilal, as found in Jami al-Masanid by Ibn Kathir, 9/559,560, and it is in Kubra, no. 2172. This hadith has corroborating narrations, among them the preceding hadith. Shuayb is the son of Layth, and Layth is the son of Saad. Khalid is the son of Yazid, and Nadr bin Abdullah Sulami is unknown, as stated in Taqrib and other sources.