The Messenger of Allah ﷺ dispatched an army and appointed Zayd bin Haritha as their commander, saying, "If Zayd is killed, or martyred, then your commander is Jafar. If he is killed, or martyred, then your commander is Abdullah bin Rawaha."They met the enemy, and Zayd took the banner and fought until he was killed. Then Jafar took the banner and fought until he was killed. Then Abdullah bin Rawaha took it and fought until he was killed. Then Khalid bin Walid took the banner, and Allah granted him victory.The news reached the Prophet ﷺ, so he went out to the people, praised Allah and extolled Him, then said, "Your brothers have met the enemy. Zayd took the banner and fought until he was killed, or martyred. Then Jafar bin Abu Talib took the banner after him and fought until he was killed, or martyred. Then Abdullah bin Rawaha took the banner and fought until he was killed, or martyred. Then a sword from the swords of Allah, Khalid bin Walid, took the banner, and Allah granted him victory." The hadith continues.
بعث رسول الله ﷺ جيشا استعمل عليهم زيد بن حارثة، فإن قتل زيد- أو استشهد- فأميركم جعفر، فإن قتل- أو استشهد- فأميركم عبد الله بن رواحة فلقوا العدو، فأخذ الراية زيد فقاتل حتى قتل، ثم أخذ الراية جعفر فقاتل حتى قتل، ثم أخذها عبد الله بن رواحة فقاتل حتى قتل، ثم أخذ الراية خالد بن الوليد، ففتح الله عليه، وأتى خبرهم النبي ﷺ، فخرج إلى الناس، فحمد الله وأثنى عليه، وقال: إن إخوانكم لقوا العدو، وإن زيدا أخذ الراية فقاتل حتى قتل- أو استشهد-، ثم أخذ الراية بعده جعفر بن أبى طالب فقاتل حتى قتل- أو استشهد-، ثم أخذ الراية عبد الله بن رواحة فقاتل حتى قتل- أو استشهد-، ثم أخذ الراية سيف من سيوف الله خالد بن الوليد، ففتح الله عليه الحديث.
Ahmad (1750) and Nasai in Kubra (8550) both narrated it through Wahb bin Jareer, who said, my father told us, I heard Muhammad bin Abu Yaqub narrating from Hasan bin Saad, from Abdullah bin Jafar, and he related it. Its chain of transmission is sahih. The rest of the hadith is mentioned in the Book of Funerals, in the chapter on condolences.