'Verily Mainun said to al-Rida (AS), ?O son of the Prophet ... Verily I see it best for me to relinquis h the caliphate and hand it over to you and swear allegiance to you!' So al-Rida (AS) said to him, 'If this caliphate indeed belongs to you and Allah has assigned it to you, then it is not permissible for you to remove a garment that Allah has clothed you with and assign it to another instead of yourself. And if the caliphate is not actually yours then it is not permissible for you to assign to me that which is not yours [in the first place].' So Mainun said to him, ?O son of the Prophet! You have to accept this post!' to which the Imam replied, 'I will never do that will ingly... for by that [i.e. my acceptance of it] you want the people to say: ?Ali b. Musa al-Rida did not abstain from worldly pursuits [of leadership] but it is the world that has turned its back on him! Do you not see how he accepted to be the heir apparent in his greed for the caliphate?! So Mainun became enraged and said, '...I swear to Allah, if you do not accept the position of heir apparent I will force you to it. So you had better accept it or else I will behead you.'