٨٠- وروى محمد بن عبد الله بن الأفطس قال: دخلت على المأمون فقربني وحياني،ثم قال: رحم الله الرضا عليه السلام ما كان أعلمه. لقد أخبرني بعجب. سألته ليلة وقد بايع له الناس فقلت: جعلت فداك،أرى لك أن تمضي إلى العراق وأكون خليفتك بخراسان. فتبسم ثم قال: لا،لعمري ولكن من دون خراسان بدرجات. إن لنا هنا مكثا ولست ببارح حتى يأتيني الموت ومنها المحشر لا محالة. فقلت له: جعلت فداك، وما علمك بذلك؟فقال: علمي بمكاني كعلمي بمكانك. قلت: وأين مكاني، أصلحك الله؟فقال: لقد بعدت الشقة بيني وبينك. أموت بالمشرق وتموت بالمغرب. فقلت: صدقت. والله ورسوله أعلم وآل محمد. فجهدت الجهد كله وأطمعته في الخلافة وما سواها فما أطمعني في نفسه.
H 80 - Muhammad bin Abdullah bin Aftas says: I entered the assembly of Mamun; he seated me close to him and asked about my well being. After that he said: May Allah have mercy on Ridha as no one was more learned than him. After people paid allegiance to him, one evening, I posed a question to him and in reply to it he mentioned a very strange matter. I asked: May I be sacrificed on you, I see your well being in the fact that you go to Iraq and I remain in Khorasan as your successor. The Imam smiled and said: No, by my life! Before I leave for Khorasan, the scroll of my deeds would be wrapped up [allusion to his demise]. There is a halt for us in this place and I will not leave till my demise approaches, and definitely my end will be in Khorasan only. I said: May I be sacrificed on you, how do you know this? He replied: My knowledge about my place is like my knowledge about your place. I asked: May God bless you, what is the location of my demise? He replied: The distance between me and you is very much; I would pass away in the east and you will die in the west. I said: You are right. Almighty Allah, His Prophet and Aale Muhammad  are most knowledgeable. After that I tried my best to allure him to Caliphate, official posts and other ranks, but he was not allured and did not accept.