Musnad Ahmad 20:10

Wahb ibn Jarir narrated to us, my father narrated to us, he said: I heard Muhammad ibn Abi Ya’qub narrating from al-Hasan ibn Sa’d, from ‘Abdullah ibn Ja’far, he said: The Messenger of Allah (peace and blessings of Allah be upon him) sent an army and appointed Zayd ibn Harithah over them, saying: "If Zayd is killed—or martyred—then your commander is Ja’far. If he is killed—or martyred—then your commander is ‘Abdullah ibn Rawahah." They met the enemy, and Zayd took the banner and fought until he was killed. Then Ja’far took the banner and fought until he was killed. Then ‘Abdullah ibn Rawahah took it and fought until he was killed. Then Khalid ibn al-Walid took the banner, and Allah granted him victory. News of them reached the Prophet (peace and blessings of Allah be upon him), so he went out to the people, praised Allah and extolled Him, and said: "Your brothers met the enemy. Zayd took the banner and fought until he was killed—or martyred. Then Ja’far ibn Abi Talib took the banner after him and fought until he was killed—or martyred. Then ‘Abdullah ibn Rawahah took the banner and fought until he was killed—or martyred. Then a sword from the swords of Allah, Khalid ibn al-Walid, took the banner, and Allah granted him victory." He waited, then he waited for the family of Ja’far for three days before coming to them. Then he came to them and said: "Do not weep for my brother after today. Call my nephews to me." He said: We were brought as if we were chicks. He said: "Call the barber to me." The barber was brought and he shaved our heads. Then he said: "As for Muhammad, he resembles our uncle Abu Talib, and as for ‘Abdullah, he resembles my character and my appearance." Then he took my hand and raised it, and said: "O Allah, be the Successor to Ja’far in his family, and bless ‘Abdullah in the transaction of his right hand." He said it three times. He said: Our mother came and mentioned our orphanhood to him, and she began to speak of his virtues. He said: "Do you fear poverty for them while I am their guardian in this world and the Hereafter?"