It is stated by Al-Fakhri that there were some of the relatives of Musa Ibn J’afar who were envious of him and carried false reports about him to Al-Rashid, saying, “The people paying him the Khums, or one fifth of the property, are accepting the Imamat and he is about to revolt against you”. They brought this report to Al-Rashid so frequently that it made him anxious and agitated. He gave the accuser some money to keep bringing him more information. But it is related through authentic sources that this relative of the Imam did not have the chance of enjoying that reward for espionage, for as soon as he reached Madinah, he suffered a serious illness and died from it. It was in that year that Al-Rashid went on the pilgrimage, and when he arrived in Madina, he arrested the Imam Musa Ibn Ja’afar, brought him to Baghdad and imprisoned him under the care of al-Sindi ibn Shahik. (Al-Fakhri-Ibnul Tiktika). This agrees with Majlisi’s comment in Bihar al Anwar that “Harun took him from Madina ten days from the end of the month of Shawwal 177 Hijiri. Then Harun set out for Makka and took the Imam with him when he returned to Basra and had him imprisoned with Issa. About one year later he was taken out of the Basran prison and taken to Baghdad. He was put in prison there under the watchful eye of the most cruel person named al-Sindi. Majlisi goes on to say that the Imam died in his prison and was buried in the cemetery of Qoraish on the south side of Baghdad.
Al-Fakhri adds,” Al-Rashid was at Rakka and sent orders that he should be put to death. They then brought a number of so called reputable men to Karkh to act as coroners and to testify publicly that the Imam died a natural death. The place he was buried was a cemetery of the Qoraish. But soon this place became the focus of pilgrimage on the grave of the Imam. A town grew around the grave yard. The name of the town became Kazimiya, the town of the Imam Kadhim (a.s.) A reputed school of theology was founded in this town which is still a source of learning for many students from all over the world.
In one of his Hadith he says:Plants grow in plain, not rocky, lands. In the same way, wisdom will grow in the hearts of the modest, not the arrogant, because Allah has made modesty the instrument of the mind and made arrogance the instrument of ignorance.