Sayyiduna Umarah bin Hazm (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) saw me sitting on a grave and said: "O you sitting on the grave! Get down from the grave; do not harm the occupant of the grave, nor let him harm you."
Al-Tabarani recorded it in al-Mu'jam al-Kabir. Its chain contains Ibn Lahi'ah; he has been criticised, and he has also been declared trustworthy.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 4321