Salma bin Nabayt سلمة بن نبيط · Chapters Regarding Funerals

“When the Messenger of Allah (ﷺ) died, they differed as to whether his grave should have a niche or a ditch in the ground, until they spoke and raised their voices concerning that. Then ‘Umar said: ‘Do not shout in the presence of the Messenger of Allah (ﷺ), living or dead,’ or words to that effect. So they sent for both the one who made a niche and the one who dug graves without a niche, and the one who…

“When Ja’far was killed, the Messenger of Allah (ﷺ) went to his family and said: ‘The family of Ja’far are busy with the matter of their deceased, so prepare food for them.’” (One of the narrators) Abdullah said: "That continued to be the Sunnah, until innovations were introduced, then it was abandoned."