Musannaf Ibn Abi Shayba 36:440

Abu Usama narrated to us, from Mahdi ibn Maymun, from Muhammad ibn Abdullah ibn Abi Ya'qub, from al-Hasan ibn Sa'd, who said: When the news of the killing of Zayd, Ja'far, and Abdullah ibn Rawaha came to the Prophet, may Allah bless him and grant him peace, he announced their deaths to the people. He left Asma' until she shed her tears, then he came to her and consoled her. He said, "Bring my brother's sons to me." She brought three sons, as if they were chicks. He called for the barber, and he shaved their heads. He said, "As for Muhammad, he resembles our uncle Abu Talib. As for 'Awn, he resembles my character and my appearance. As for Abdullah," and he took his hand and raised it, then said, "O Allah, bless the transaction of his right hand." Their mother began to rejoice for them. The Messenger of Allah, may Allah bless him and grant him peace, said to her, "Do you fear poverty for them while I am their guardian in this world and the Hereafter?"