Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: the Prophet (peace and blessings be upon him) appointed Sayyiduna Zayd bin Harithah (may Allah be pleased with him) as commander in the Battle of Mu'tah and said: "If Zayd is martyred, then Ja'far; and if Ja'far is martyred, then Abdullah bin Rawahah." Sayyiduna Abdullah (may Allah be pleased with him) said: I was with them in that battle. We searched for Sayyiduna Ja'far (may Allah be pleased with him) and found on the front of his body more than ninety wounds, from spears and arrows.
Hadith Referenceالمعجم الكبير للطبراني / باب الجيم / 1450