Musannaf Ibn Abi Shayba 27:559

'Abd al-Rahim ibn Sulayman narrated to us, from Isma'il ibn Abi Khalid, from 'Amir, who said: I was informed that the Prophet, peace and blessings of Allah be upon him, sent word to the wife of Ja'far, saying: "Send the sons of Ja'far to me." He said: So they were brought to him. He then said: "O Allah, indeed Ja'far has come to You to the best of rewards, so succeed him in his offspring with the best [way] You have succeeded any of Your righteous servants."