Sunan Ibn Majah, Volume 2, Book 6, Hadith 1566 (DarusSalam) ⓘ
It was narrated from Abu Hurairah said: The Messenger of Allah said: “If one of you were to sit on a live coal that burns him, that would be better for him than if he were to sit on a grave.”
حَدَّثَنَا سُوَيْدُ بْنُ سَعِيدٍ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ أَبِي حَازِمٍ، عَنْ سُهَيْلٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لأَنْ يَجْلِسَ أَحَدُكُمْ عَلَى جَمْرَةٍ تُحْرِقُهُ خَيْرٌ لَهُ مِنْ أَنْ يَجْلِسَ عَلَى قَبْرٍ " .
also referenced under: Hadith 1566 (Reference) & Book 6, Hadith 1633 (In-Book)