The blood relationship is touching and close.

The blood relationship is touching and close. The lineage is one. Al-Abbas is the uncle of the Prophet, may Allah bless him and his family, and full brother of his father. He is the uncle of Ali b. Abi Talib and full brother of his father. May Allah not send you far from doing that. He has opened you hand, made your origin honorable, and made high your lineage. -Certainly, I will do that, Abu al-Hasan.

-Surely Allah, the Great and Almighty, has made it incumbent on rulers to relive the poor from among the community, to pay the debts of the indebted, and to clothe those naked. You are appropriate to do that. -I will do that, Abu al-Hasan. Then the Imam, peace be on him, went away. Harun rose to honor him; he kissed him on the forehead. Then he turned to his children and said to them: Go before your uncle and master; take the stirrup; arrange his clothes; and accompany him to his house.

They set out to serve the Imam. Meanwhile, the Imam, peace be on him, confided a secret to al-Mamun. He gave him good news of that he would be a caliph. He asked him to be kind to his children. After they had served the Imam and accompanied him to his house, al-Mamun said: I was the boldest of the children of my father (in asking him). When the people scattered, I (al-Mamun) asked him: -O Commander of the faithful, (a man came in).

You magnified (the man), rose for him from your gathering, received him, seated him in front of the gathering, sat down behind him, and then you ordered us to take the stirrup on his behalf. Who was that man? -This is the Imam of the people, the Proof of Allah's mercy to His creation (Hajjatullah) and His caliph among His servants. O Commander of the faithful, do these qualities not belong to you? Are they not in you?

-I am outwardly the Imam of the masses by force and through oppression, while Musa b. Jafar is the Imam in truth. And surely he, by Allah, is more worthy of being the successor of the Messenger of Allah as the caliph than I am and anyone else among all the people. And by Allah, If you yourself attempt to take such caliphate from me, I shall take it away from you even if that means gouging your eyes, for power is blind. Harun remained in Yethrib (Medina) for some days.

When he intended to leave, he ordered a little amount of money to be given to the Imam; the amount was two hundred dinars. He asked al-Fedl b. al-Rabi to apologize to the Imam on his behalf.