Musnad Ahmad 658:153

'Abd al-Razzaq narrated to us, Sufyan narrated to us, from al-A'mash, from al-Minhal, from Zadhan, from al-Bara' ibn 'Azib, who said: "We went out with the Messenger of Allah, peace and blessings of Allah be upon him, for a funeral. We found the grave, and it had not yet been dug (as a lahd/niche). So he sat down, and we sat down."