Here is a question:
The Imam (A.S) reasoned to accept Ma'mun's succession by citing a verse from the Quran due to denying the permission of self-induced in destruction when he was threated to be killed. He accepted the succession with the above mentioned conditions. In other words, he accepted the succession in order to avoid killing by a sword, but Ma'mun made the Imam (A.S) to eat poisonous grapes and pomegranates and the Imam (A.S) knew that poisonous grapes would kill him, but he ate. The question is: Why didn't the Imam (A.S) avoid eating grapes? Was eating grapes self-induced in destruction?
The key point is answering this hidden issue.
As we mentioned earlier, the Imam (A.S) followed four issues:
1. Avoiding vanishing or weakening the central government against atheists who constantly molested the state borders. If the central government of Abbasid had become loose to deal seriously with them and they had controlled the government, they would not have observed any limitation and they would have destroyed everything.
2. Avoiding deviating public scholars who were admitted by the government and confirmed the government. Although these sorts of scholars didn't accept Imams' Imamate, Shi'a Imams were trying to decrease these scholars' deviation of authentic Islam by inducting authentic Islamic teachings and encouraging them to traditions of the Prophet Muhammad (S.A.W). He, also, encouraged them to stay in the way of Islam.
3. Avoiding vanishing and destroying Shi'a, which had been just a minority and turned to an accepted organization. They were training, educating and developing human resources in various points. The least mistake in dealing with Ma'mun and Abbasid could have made an excuse for killing Shi'a leaders.
4. Avoiding Shi'a deviation;
5. Revealing the nature of Abbasid and their deviation from the right path.
Imam's entrance to the government was efficient for developing Shi'a and eradicating some problems arisen for Shi'a. In addition, it could open the environment for Shi'a's cultural plans. As the Imam (A.S) entered the government and became the successor of Ma'mun, Shi'a situation and his followers meaning the successor's friends and caliph's successor totally changed, which was a big barrier against the rulers and mayors of Abbasid to press on Shi'a.
The rulers and mayors of Abbasid were not justified for Ma'mun's purpose of Imam Reza (A.S)'s succession. If they knew, they had to pretend not to know about Ma'mun's purpose until Ma'mun pretended to behave well with the Imam (A.S). Therefore, the followers and relatives of the Imam (A.S) were working in various points using the title of succession. Nobody could protest them. They managed to revive Shi'a's beliefs by holding classes and establishing lesson rings.
People such as Muhammad ibn – iAbi Amir who tolerated a hard condition in Aaron's period, imprisoned, and were tortured, they could train, educate, and develop Shi'a beliefs safely.
On the other hand, Imam's entrance to Abbasid organization could have been deviating for Shi'a who might suppose that Abbasid organization was what Imams (A.S) were going to achieve it and may be deviated about Ma'mun in Judgment. The Imam (A.S) removed such an imagination by written conditions in his agreement with Ma'mun to some extent.
The public scholars had an opportunity to connect more with the Imam (A.S) by Imam's entrance to this position. The Imam (A.S) transferred to them Islam beliefs and they listened to Imam's (A.S) traditions. The people such as Ahmad ibn – i-Hanbal and ibn – i-Edris, the chairman of Shafei sect, are among those people who connected Imam's follower, took advantage of his traditions or connected to the Imam (A.S) himself.
Naturally, when the Imam (A.S) was with Ma'mun, Ma'mun had to superficially observe plenty of Islamic rules, avoid injustice and oppression in his judgment, and had to consider Imam (A.S)'s opinion in his judgment.