Imam lived for a year in Baghdad with Ummul Fadhl. She was very disobedient to Imam. When she found out that Imam had another wife (from the progeny of Ammar-e-Yasir) and that there was also children she was jealous and angry realizing that her father's plan had failed. She complained to her father who also realized that his plan, to keep the 12th Imam in his progeny, had failed.
He was enraged and in his rage he drank heavily and went to the 9th Imam's house and attacked Imam with a sword. Both Ummul Fadhl and a servant saw the attack and believed Imam was dead. Mamun on waking next morning realized the consequences of his attack and was thinking of arranging the disposal of Imam's body when he saw Imam well without a scratch on him.
He was confused and asked Imam who showed him an amulet which is called Hirze Jawad.The Holy Imam told him it was from his grand mother Bibi Fatima Zahra (A.S.) and kept the wearer safe from all except the angel of death.
We, also, observed how Ma'mun held meetings and councils in which he invited various scholars, thinkers and jurisprudents like the Qadi ul-Qudat(Chief Judge) of the Abbasid state, Yahya bin Aktham for scholarly discussions and debates which lasted hours and days. In such meetings, they introduced the Imam Jawad (A.S..) to critical legislative and theological questions to which he answered wisely and accurately.
The debate was attended by top officials of the state, military commanders and leaders.Then, the Qadi, Yahya bin Aktham approached Abu Ja'far al-Jawad (A.S.) and asked him some questions he had prepared before. The Imam Jawad (A.S.) answered them correctly and, in which, he showed the cause for correcteness.
Therefore, the debate went on between Yahya and Imam al-Jawad (A.S.) in the following way:
Ask me whatever you wish," said the Imam in the typical tone of his anscestors
Yahya, then, asked the Holy Imam, "What is your verdict about a man who indulges in hunting while he is in the state of Ihram'. (In the code of religious law hunting is forbidden for a pilgrim).
The Imam at once replied, "Your question is vague and misleading. You should have definitely mentioned whether he hunted within the jurisdiction of the Ka'ba or outside; whether he was literate or illiterate; whether he was a slave or a free citizen; whether he was a minor or a major; whether it was for the first time or he had done it previously; also, whether that victim was a bird or some other creature; whether the prey was small or big; whether he hunted in the day or at night; whether the hunter repented for his action or persisted in it; whether he hunted secretly of openly; whether the 'Ihram' was for Umra (the lesser pilgrimage) or for Hajj (the greater pilgrimage). Unless all these points are explained no specific answer can be given to this question.".
Qadi Yahya was bewildered and staggered in listening to these words, of the Holy Imam, and the entire gathering was dumbfounded. Inability and indecision were clear on Qadi Yahya's face.
Thus, the historical period, and what it contains of religious scholars and jurisprudents, acknowledges the leadership of Imam al-Jawad (A.S.) in order to continue the right path of his forefathers and their footsteps and, also, bear the religious scholarly and political burdens of divine succession of the Holy Prophet (S.W.A).