During the tenure of Imam Ja’far as-Sadiq (a.s) the ruling power was in the hands of Mansur Dawaniqi, who had wrought destruction upon the Hasani Sadat (Descendants of Imam Hasan). Mansur wanted to make Imam Ja’far as-Sadiq (a.s) his obedient one and that Imam (a.s) may begin to accept him as his leader. But he was not able to achieve his. When he realized that the Imam couldn’t come into his control through this manner he became more infuriated. One day he said to the Imam, “Your example for me is like a bone stuck in the throat.” He replied, “Your suspicion is baseless. I do not interfere in any of your governmental matters. Why do you consider my guidance and teachings harmful? And why do you trouble me all the time? He said, “I consider your teachings anti-government, and thus command you to stop your classes and lectures.”
Imam (a.s) said, “I seek Allah’s forgiveness! Who can dare restrain me from the propagation of truth?” Mansur said, “If you do not give it up I would have you killed.” Imam said, “Do you threaten me with murder? The Ahl ul-Bayt have always been martyred and imprisoned in the process of spreading the truth?” Mansur said, “I am the Caliph of the time. My obedience is incumbent on you.” Imam said, “No ones obedience is incumbent on us, Ahl ul-Bayt. Rather our obedience is obligatory on everyone.”
Reference :Akhlaq al-A’imma, Morals & Manners of the Holy Imams