An Interesting Anecdote
One of the interesting and often narrated anecdotes says that Da'bal left Marw after Da'bal had already said his famous poem rhyming in the `t' and passed by the watering place belonging to Fawhan when highway robbers intercepted his caravan and took it all as a booty after tying its men including Da'bal. The robbers took possession of all the wares of the caravan and kept dividing it among themselves when one man, quoting Da'bal, said: I find others share their share,
Their hands of what is theirs are bare...,
Da'bal heard him and asked him, "Who said that line?" The man answered, "A man from the tribe of Khuza'a called Da'bal ibn Ali." Da'bal said, "I am Da'bal who composed that poem, and this verse is one of its verses," whereupon the man leaped and rushed to their chief who was saying his prayers on top of a hill, and he was a Shi'a. He told him what he had heard. The chief came and asked Da'bal if he was the man and Da'bal answered in the affirmative, so the man challenged him to recite the entire poem. When he did, he untied him and untied all the other men in the caravan and returned all their belongings back to them just to please Da'bal.122
This story, although we are not sure if it is true, expresses anyway the implication this verse carries.

Opponents of the Regency Arrangement
The regency arrangement was the source of horror mixed with outrage and anger of the Abbasides and their followers, and this became manifest by their removal of all political influence of al-Mamoon from Baghdad and by reneging on their pledge of allegiance to him which caused him a great deal of political disasters.
There was also a group of men among his closest courtiers and leaders who refused to endorse his decision and spoke of their disagreement with him and insisted on their disagreement till he found himself forced in the end, according to some reports, to arrest them for fear of foiling his plan. Among those arrested were three men, namely al-Jalloudi, Ali ibn Abu Imran, and Ibn Munis. Al-Saduq narrates saying that they were killed after being arrested123, although some historical facts conclude that this was not so, for both Tabari and Ibn Athir, discussing the events of the year 205 A.H., say that al-Mamoon appointed Yazid ibn Isa al-Jalloudi to fight al-Zatt in Yemen124, and so does al-Yaqubi.

Researching History
We find it hard to believe that the al-Jalloudi whom al-Mamoon killed was not the same al-Jalloudi who fought al-Zatt, and it is possible that he was not killed because of the intercession on his behalf by Reza(A.S.).
It is strange that those leaders should revolt against the wish of al-Mamoon and insist on their rebellion and dissension to the extent that they were executed, and here we have no choice except to endorse the authenticity of this story according to the common books of criteria in understanding history. Al-Saduq narrated the story of their execution in a way which was closer to a stage play, in which he used precision to distribute the roles among it cast, than anything else. It is likely that Ali ibn Abu Imran whom al-Saduq named among those three men was actually Abdul-Aziz ibn Imran who will be discussed later and who was killed with others by al-Mamoon after having been accused of taking part in the murder of al-Fadl ibn Sahl.

Silent Opposition
There were other elements of dissent who did not relish the nomination of the Imam (A.S.) as the successor and to the possibility of taking caliphate out of the Abbasides, but they submitted to reality while hiding ill intentions just to avoid a clash with the government in which they are not strong enough to oppose its will. But they could not keep it to themselves for too long; instead, they expressed the bitterness they felt towards such an "irresponsible" act, according to their way of thinking, of the caliph.
Ishaq ibn Mousa ibn Isa ibn Mousa accompanied a group of people for the hajj where he prayed for al-Mamoon and for his successor Ali ibn Mousa Reza(A.S.), whereupon he was challenged by Hamdawayhi ibn Ali ibn Isa ibn Mousa ibn Isa ibn Mahan who leaped at him and called for a black (Abbaside colour) robe to wear, and when he could not find one, he took a black flag and wrapped himself in it saying: "O people! I have now conveyed to you what I was ordered to convey, and I do not recognize anyone other than the commander of the faithful and al-Fadl ibn Sahl," then he descended.125 This incident leads us to believe that there was a silent underground opposition which did not wish to enter into a struggle to define its position regarding the government, in addition to the opposition which had already and publicly taken a stance contrary to the will of the government as had happened in Baghdad and elsewhere.
At any rate, those who rejected the regency arrangement did not realize what prompted al-Mamoon to bring it about during those shaky political circumstances which the Abbaside government lived, and al-Mamoon was not naive enough to reveal to these parties the secret which he had very well kept to himself till he reached the final destination point of the plan he had planned.

Eid Prayers
One of the manifestations which was not destined to finalize of the regency celebration was the Eid prayers which al-Mamoon insisted that the Imam (A.S.) should conduct in person because he himself had caught a very bad cold, or he may have had another excuse. Al-Irshad quotes Ali ibn Ibrahim who in turn quotes Yasir the servant and al-Rayyan ibn al-Salt saying that when the Eid approached, and Reza(A.S.) had already been named as the caliph's successor, al-Mamoon invited him to ride to the place where the occasion was to be celebrated and to say the prayers and deliver the sermon, and Reza(A.S.) sent him a word saying, "You know what terms exist between both of us; so, please exempt me from conducting the prayers to people." Al-Mamoon answered saying, "My intention is that people's hearts must rest at peace regarding you and they should come to know your excellences." Messengers kept going between both men carrying messages and when al-Mamoon insisted on his suggestion, he sent him a message saying, "If you exempt me, I would appreciate it, and if you do not, I shall come out just as the Messenger of God (S.A.W.) and the Commander of the Faithful Ali ibn Abu Talib (A.S.) did," whereupon al-Mamoon said, "Come out however you please," and he ordered the leaders and chamberlains and the public to go early to al-Rida's house. People waited to see Abul-Hassan Reza(A.S.) in the alleys and on rooftops, and women and children too gathered waiting for him to come out. The army commanders and their troops stood guard at his door mounted on their horses till the sun started rising. Abul-Hassan washed, put on his outside clothes and wore a turban made of cotton, leaving a portion of it drape down on his chest and a small portion of it between his shoulders. He rubbed his hands with some perfume and took in his hand a cane and told his servants to do likewise. So they all came out, and he was barefoot, and he raised his trousers up to half the leg and his clothes were hanging loosely on him. He walked for a short while, raised his head above and made the takbir and his servants did likewise. Then he walked till he reached his doorstep. When the leaders and troops saw him looking like that, they all alighted in the speed of lightning, so much so that lucky was the one among them who happened to have a knife to cut the leather stirrups so that he could jump faster than others, take his sandals off and remain barefoot just as the Imam (A.S.) had done. Reza(A.S.) made takbir again, and everyone else did likewise, so much so that it seemed to everyone as if the sky and the walls echoed with him, and Marw was shaken with the noise of weeping and hassle when its residents saw Abul-Hassan and heard him say Allahu Akbar! Allahu Akbar!...

Sending Imam Back
Al-Mamoon came to know about all of that. Al-Fadl ibn Sahl Dhul-Riyasatayn said to him, "O Commander of the faithful! If Reza(A.S.) reaches the mosque in such a condition, people will be fascinated by him and we all will have to fear for our lives; so, send him a messenger and tell him to go back." Al-Mamoon sent him a message saying, "We have over-burdened you and wore you out, and we do not wish that you should suffer any hardship on our account; so, go back home, and let people say their prayers behind whoever they have been praying." Abul-Hassan, therefore, asked for his sandals back, put them on and went back. People on that day differed regarding their prayers, and he did not participate in their prayers.

Analyzing Imam's Handling of Eid Prayers
Thus did the Imam (A.S.) desire to give the Eid prayers their great spiritual meaning and separate them from the fake appearances which were attached to them by ruling caliphs who were using them to make a display of the power they commanded and to secure the sense of awe and greatness in the minds of the public. Such a splendid show whereby the Imam (A.S.) tried to bring the legislative system back to its pristine genuineness was something with which the public were not familiar at all, and it was a magnificent surprise that the emotions of the masses were amalgamated with the Imam's position which was rebellious in nature against the traditions followed by the caliphs on such occasions.
People lived during those moments a supreme spiritual outburst which deepened within their souls the sense of belief and distanced them from artificial and fake appearances. Such an objective stance the Imam (A.S.) took was an open invitation to the nation to reevaluate the ruling apparatus that played havoc with their lives and properties, and inspire to them to see how fake the government apparatus was and how distant from the reality of the Islamic message. This is why al-Fadl was swift to warn al-Mamoon about the embarrassment of the situation and alert him against people falling in love with the Imam (A.S.) and turning in hatred against the government if he did not send the Imam (A.S.) back. Al-Mamoon was moved by al-Fadl's warning; therefore, he had to send someone to ask the Imam (A.S.) to go back home.

Some of the Imam's Dawah Methods
The Imam (A.S.) had his own particular method in promoting the dawah, for he took advantage of some exciting situations in order to open people's eyes to see how corrupt the government and its ruling system was, having no freedom of movement due to the restrictions al-Mamoon and his minister al-Fadl ibn Sahl had enforced on him of strict surveillance over all his actions and speeches. Among such situations which were dictated by the nature of his mission was his conditional acceptance of the regency that he would not have to issue orders nor cancel the orders of others, that he would not depose or nominate anyone, nor have anything to do with the state affairs. All in all, this indicates that he did not feel that the government was legitimate enough for him to cooperate with and which would raise some questions by people around him.
A final note. This is the story of the regency issue. I have tried while writing it to be faithful to history in discussing its complexities and developments without having any goal except to clear the Imam (A.S.) of the accusations against him which may still be raised by some people who have a particular way of understanding history within the frameworks of texts without examining the main subject-matters while studying history. These include: the evaluation of the general circumstances, the political impacts which stamp the nature of a government, the social pressure which may have something to do with defining some situations and taking a few steps dictated by the necessity of coping with a government. How nice it would be if the long story of history were researched on the basis of analyzing the situations and evaluating the circumstances! It is only then that the cloud would be removed from a great deal of scenes and pictures, and we can be more realistic in our judgement of events.

Imam's Role in Eliminating al-Fadl ibn Sahl
Al-Mamoon granted al-Fadl the nucleus of power and his complete personal confidence when he permitted him to fare with all government issues, vesting upon him the responsibility of all state affairs without doubting even a little bit his loyalty and readiness to consume himself while safeguarding him and his throne.
Al-Fadl, on the other hand, made very good use of that confidence and generous award for the enhancement of his own status. He took hold of the reins of government and surrounded al-Mamoon with a curtain of deception, completely isolating him from the reality of the general political situation, acting on his own according to the dictates of his own interest as an absolute ruler single-handedly issuing decisions suitable to strengthen his own position.

Al-Fadl Controls the Government
With the talent of cunning and conniving, al-Fadl was able to control the sentiments of the leaders and heads who made up the governing apparatus, forcing upon them his own power and awe without anyone being able to go beyond the limits al-Fadl had defined for him, for the price would then be the loss of his job and maybe his life as well.
The only person whom he could not control nor influence was Imam Reza(A.S.) who was closely watching the suspicious movements of al-Fadl, trying from a distance to warn al-Mamoon against the sure danger awaiting him due to the actions of al-Fadl and his supporters, but al-Mamoon did not want to show any sign of mistrust of the man who saved his power and returned his usurped throne to him after the winds of dissension emanating from Baghdad almost eliminated him and his government.

Al-Fadl Tests al-Mamoon's Attitude Towards Him
Al-Fadl was not completely unaware of the secret warnings to al-Mamoon regarding his suspicious movements and what political gains he aspired to achieve in order to satisfy his aspirations and ambitions for which he had prepared plans with sure results.
Al-Fadl may have been contented with the strength of his own position and the invulnerability of the plans he had prepared to secure the safety of his status, without imagining that al-Mamoon might one day consider eliminating him. In Khurasan, he controlled all the centers of power by winning the support of the leaders and chiefs there. In Iraq, he was able through his cunning to depose Tahir ibn al-Husayn from the post of leadership after he had subdued Baghdad to his control when al-Mamoon instructed al-Fadl to depose Tahir and banish him to Riqqa and install his own brother al-Hassan ibn Sahl in his place, and al-Mamoon immediately responded favourably to that.
Such a swift positive response from al-Mamoon was a clear signal to al-Fadl that he was the only man who monopolized control over the center of power and who could control al-Mamoon's mind regarding how to run the government, and that the whisperings which started being circulated inside closed halls suggesting a change in al-Mamoon's heart towards al-Fadl were completely far away from the truth.

Ambiguity of al-Mamoon's Handling of al-Fadl
We cannot understand the secret in the continuation of such a loose stance of al-Mamoon towards al-Fadl and whether it was due to a secret plan al-Mamoon had prepared to trap al-Fadl and get rid of him after going beyond reasonable limits in his control over the running of the general administration of the government. Was that the outcome of the element of trust in al-Fadl's actions and the complete confidence in his loyalty after all the sacrifices he had offered in order to bring authority back to him?
In fact, al-Mamoons's political insight and genius, and his alert awareness of events, make us doubt the second portion of this rhetorical question, for al-Mamoon was not a naive person who tried hard to freeze himself and practically isolate himself from government, while his minister had a free hand to do whatever he wished and whatever his own ambitions dictated to him.

Elimination of Harthama
No matter what the reason was, there are historical evidences asserting to us the fact that al-Mamoon was not reserved in adopting some suggestions inspired by al-Fadl. For example, Harthama was one of the leaders who did a very good job in creating a military atmosphere conducive to al-Mamoon's government and in securing its foundations. At the same time, he was one of those who were critical of the policies of al-Fadl and his brother al-Hassan ibn Sahl. Like other leaders, he did not appreciate such an extravagant norm of conduct adopted by al-Hassan ibn Sahl in his dealing with other leaders and chiefs and, in his view, that was according to instructions from his brother al-Fadl and to a plan agreed upon by both of them. For this reason, he decided to speak his mind to al-Mamoon and to acquaint him with the disturbing situation clouding the government and with the failure of the extravagant policy adopted by al-Fadl and his brother.