The boundaries of Fadak
The following article is a conversation between Imam al-Kazim ع and Harun ل discussing the boundaries of Fadak
The latter used to say to Imam Musa ibn Ja’far ع
“O father of al-Hassan ! Accept Fadak so that I may give it back to you,” but he always used to refuse. Harun kept insisting till the Imam (as) said, 'I shall not accept it except when its boundaries are defined' 'What are its boundaries ?' Harun asked him. 'O Commander of the faithful' responded the Imam (as), 'If I define its boundaries, you will not give it back to me' Harun said, 'I plead to you in the name of your grandfather (the Prophet ﷺ ) to do just that' The Imam ع said, “The first boundary is 'Aden' . Harun's face changed color and said, 'Eh !' The Imam (as) went on to say, 'The second boundary is Samarkand'. Harun's face was clouded with outrage. The Imam ع added, 'And the third boundary is Africa' Now Harun's face became so dark, it looked black and said, 'Eh !' The Imam ع said, 'And the fourth lies beyond the Caspian Sea and Armenia' Harun said: Nothing remains for us; so, move over and take my seat on the throne' Imam Musa al-Kazim ع said, 'I have told you already that if I define it, you will not return it'
It was then that Harun decided to kill the Imam ع , handing over such a task to Yahya ibn Khalid....
Source :
Al-Insan wal Hayat, pg 271
Manaqib e Aal Abi Talib, volume 4, pg 320