Bulugh al-Maram 3:62

‘Abdullah Ibn Ja’far (RAA) narrated, ‘When we received the news of Ja’far’s death; when he was killed (in the Battle of Mu’tah), the Prophet(ﷺ) said:

“Prepare some food for the family of Ja’far, for what has befallen them is keeping them preoccupied.” Related by the five lmams except for An-Nasa’i.