Narrated Abu Sa’id Al Khudri :
The Messenger of Allah (ﷺ) as saying: When you follow a funeral, do not sit until the bier is placed (on the ground).
Abu Dawud said: This tradition has been narrated by al-Thawri (i.e. Sufyan) from Suhail, from his father on the authority of Abu Hurairah. This version has: until it (the bier) is placed on the ground. It has also been narrated by Abu Mu'wiyah from Suhail. This has: Until it is placed in the grave.
Abu Dawud said: Sufyan's version is more guarded than that of Abu Mu'awiyah.