The analysis of the discussion between the Imam (A.S) and Mamun
Aba Salt said:
Ma'mun told the Imam (A.S): "As I know your virtue and knowledge and piety and purity and devotion, you are more qualified for caliphate."
The Imam (A.S) replied: "God's slavery is my honor. I am pious in the world in order to save myself from it. I avoided sins in order to reach special degrees and I am humble to reach God's closeness."
Ma'mun said: "I'm going to deliver you the government and I pledge allegiance to you."
The Imam (A.S) replied: "If the government is your right and God has specified it for you, so you must not deliver it to others. If the caliphate is not your right, you cannot grant me what is not related to you."
The Imam (A.S) expressed everything right for Ma'mun and condemned him in a short reasonable speech.
Ma'mun might suppose that the Imam (A.S) would refuse to accept the government, then Ma'mun could pretend that the Imam (A.S) didn't define any right in the government and he didn't know the government as his job; otherwise, he would have taken this responsibility. Therefore, he could have undermined the philosophy of Imamate and leadership.
Imam (A.S)'s reply challenged him so hard that whether my government is related to you. You should do your responsibility and determine your duty whether you have any right in the government.
Here, The Imam (A.S) put an emphasis on this point that the right of caliphate is not the same as other rights, so human being cannot ignore to resign it if he is the ruler. Therefore, the caliphate is whether the duty in which it ought to be done or it's not personal in which its seizure or interference is unlawful.
If God assigns you as a caliph, how can you avoid doing it? If God doesn't do so, do you have any permission to interfere in it?
Here, Ma'mun stopped his lies and revealed his real nature and said:
"You must accept it."
The Imam (A.S) told again: "If I myself should decide, I will never accept it."
Ma'mun didn't follow his request any more. Some days passed. Ma'mun was trying to persuade the Imam (A.S) until he let down and said to him: "If you are not pleased with my allegiance with yourself, at least accept my succession so that the caliphate will be yours after my death."
The Imam (A.S) said: "My fathers (the previous Imams (A.S) narrated from Prophet Muhammad (S.A.W) that I will be killed by poison before you and I will be buried next to Aaron's tomb."
Ma'mun said crying: "The son of God's prophet! Who dares to do so while I'm alive?"
The Imam (A.S) said: "If it was to be revealed, I could introduce the killer."
Ma'mun said: "You are going to be indolence. You don't accept the caliphate so that the people say that he is indifferent toward the world." When Ma'mun couldn't defraud anymore and Imam's speech challenged him and the play of succession destroyed, he started to be impolite and sabotage against Imam (A.S)'s characteristic from other aspects and accused the Imam (A.S) that you are indolence. He said: "The Imam (A.S) is going to use people by pretending to be pious and spends his life happily and he gains false legitimacy and popularity for himself."
The Imam (A.S) neutralized this conspiracy as follows.
The Imam (A.S) said: "God knows that I have not told a lie since I was a child and my reluctance to the world is not because of the world. If I want, I can say what your purpose of telling these points is."
Ma'mun asked: "What is my purpose?"
The Imam (A.S) said: "If I tell the truth, am I safe?"
He replied: "Yes."
The Imam (A.S) said: "You are going to put me in a position in which people supposed that Ali ibn – i Musa refused to be in the government not because he was pious in the world, but because he cannot get anything of the world. Now that he can be in the government, how did he accept Ma'mun's succession in the hope of reaching the caliphate?"
Naturally, the Imam (A.S) pointed out the most important factor for Ma'mun and the Imam (A.S) so as to reveal Ma'mun and mentioned that the factor was destructing Imam's personality and eradicating an established thought in people's minds.
The entire purpose of Imams (A.S) was to prove that the reign and presidency over people is not a bait which is given to humans, but also it is a heavy duty which should be carried out just by them as the assigned responsibilities knowing its requirements. The reign over people requires rich knowledge, extensive fairness, absolute justice and reluctance toward his world, all of which are found only in Imams (A.S). If others took advantage of their education and beliefs, they will gain benefit of this source of grace in acquiring degrees and can assist them in their great responsibility according to their capacity.
If this image was established for people and Imam (A.S)'s followers that all the above mentioned points were false and the Imams (A.S) were eager to gain such a power and position, it needs to destroy all the numerous hardships and trouble of Prophet Muhammad (S.A.W), the Imams and their honest followers. In other words, the destruction of the way which its followers were so little and in that time they were so much that Ma'mun had to superficially resign his reign to eradicate this great force and engaged himself with Abbasid.
The Imam (A.S) is not a person who is defeated by Ma'mun's guile, but the Imam (A.S) used all of his guile means against Ma'mun by correct and appropriate responses.
Everything was finished against Ma'mun. Therefore, he revealed his inside and said angrily:
"You abused the security I have given you and treated me inadmissibly. By God, You must accept it; otherwise, I will kill you." This sentence foiled his entire plot eternally. All the people who witnessed it found out that the acceptance of the Imam (A.S) was obligatory and involuntary.
The Imam (A.S) said: "God forbids me to prepare the means of my killing by myself. Therefore, I accept it provided that I don't participate in any Removal and installation, I don't change any custom and tradition and I will be only in the position of consultation and far from execution."
Ma'mun sufficed this extent.
Notice that the Imam (A.S) managed to take benefit of this condition to reach God's closeness by divine wisdom. He defeated Ma'mun's guile by himself in the panel discussion with Ma'mun which was apparent for others. Everything was finished against Ma'mun according to Ma'mun's final decision.