The Prophet Muhammad (صلى الله عليه وسلم):

Abu Dārda used to sit next to graves and when he was asked about this, he replied, ‘I am sitting amongst those people who remind me of the hereafter and when I leave, they will not backbite me.”

Ibn al-Jawzī [رحمه الله] - Minhaj Al-Qasideen, 432