Born in Madina on 7th Safar 128 Hijri (745AD). Died in Baghdad Iraq 25th Rajab 183 Hijri (799 AD). Period of Imamat was 35 years.
Imam Musa Ibne Ja'afar was born during the struggle between the Ummayads and the Abbasids. He was only four years old when Abul Abbas "Saffah", "The Shedder of Blood", came to the throne as the first Abbasid caliph. For twenty years he was under the authority of his father, who died ten years before the end of the long reign of Mansur. The Imamat of the 7th Imam extended through the ten remaining years of the caliphat of Mansur, and included the ten years of the rule of Mahdi, one year and some months of Hadi and about twelve years of the reign of Harun al-Rashid. Thus for thirty five years he was the Imam. He held this coveted distinction as the longest period of Imamat of the Eleven Imams.
With six brothers and nine sisters Imam Musa (AS) grew up in a large family. Ismail the oldest brother died at a young age and Musa was chosen by Divine providence to succeed his father as the Imam. There were those among the followers of the 6th Imam who thought that Imamat should be hereditary and therefore the eldest son of the 6th Imam should succeed. They misunderstood the whole concept of Imamat which was neither hereditary nor mandatory for any one person. It was divinely selected and the Imam at his death bed reveals the name of the next Imam.
The Abasid caliphs were always on the alert with this distinctive source of Imamat and our 7th Imam was fully aware of this danger. The Caliphs were on the alert to discover any real or imaginary disloyalty with the Imam or his followers and they would immediately put them under arrest. This natural anxiety, however, does not appear to have seriously interrupted his life as an Imam. He continued to disseminate Qur'anic teachings as his father Imam Ja'afar al-Sadiq (AS) used to do through the Islamic schools opened in Madina during the life of the 5th Imam.
Ibn Khalikan related that caliph Mansur saw in his dream Imam Ali (AS) who was reciting the verse from the Qur'an, "O' Muhammad, were you ready therefore, if you had been put in authority, to commit evil on the earth and to violate the ties of blood." Mansur sent for his favourite companion Ibn Younus at night and told him of his dream. He then said," Bring me Musa Ibn Ja'afar." The Imam Musa Ibn Ja'afar was brought in all the way from Madina to Baghdad. When he arrived Mansur embraced him and said to him, "Abul Hasan, I have just seen in a dream Ali Ibn Abi Talib (AS) who was reciting this verse. Give me your assurance that you will not revolt against me or against any of my children. Imam replied, By Allah I have no such intentions. The caliph then gave him a thousand dinars and restored him to his family in Madina.
This story give us some idea how these Abasid caliphs were so afraid of the Imams of Ahlulbayt that in spite of their total lack of evidence for any kind of revolt against their earthly power, they would not leave them alone. From time to time the Imams were brought in from Madina, kept in Baghdad either on house arrest or inside prisons under the most difficult of conditions. But it was the Imams great Divine Characters that managed to keep them going in the most severe of conditions. It is because of these uncertain times that the Imam said,
"How base is the world for a people, unless God give them joy; and how great is this life, if God is not angry with them." Total submission to the Will of God in all circumstances.
It was widely known that Imam Musa Ibn Ja'afar had been given powers of healing. Once he was passing by a house and heard little children weeping. He enquired as to why they were crying. He was told that they were orphans and their mother had just died and now they had no one to look after them. He went inside the house, made two prostrations and prayed to God for her life. Moments later the woman stood up well and in good health. People who saw this and cried out, "Behold it is Jesus son of Mary."
Once Harun Al-Rashid was visiting Madina. He went to the mosque of the Prophet near his grave and said, My Salams to you O' cousin of our fathers. Imam Musa was there who saluted the grave of the Prophet with the words, My Salams to you O' our grand father. At this Al-Rashid was disconcerted and went away angry.
This occurrence was sufficient to explain his first summons from Al-Rashid to come to Baghdad. There he was kept in prison. But after nearly a year in prison Harun saw in a dream that an Abyssinian slave was rushing towards him with a javelin and telling him to release Musa Ibn Ja'afar or he will slay him. Harun immediately called the head of the prison and told him to release the Imam and give him thirty thousand Dirhams. When this man reached the door of the prison he found Imam was waiting for him and welcomed him, saying how quickly he had come to release him. The man said how he knew. Imam replied "I saw the Holy Prophet in my dream who told me to recite these words and then I will be released from prison for I had been put here unjustly." The man asked what those words were, Imam replied,
O thou who hearest every voice,
O thou who lettest no opportunity escape;
O thou who clothest the bones with flesh
And who wilt raises them up after death;
I invoke thee by thy Holy name, and by that great and splendid name which is treasured up and closely hidden, by that name which no created thing shall ever know;
O thou who art so mild and whose patience is never equaled;
O thou, whose favors never cease and can not be numbered, set me free. (Masudi, Muruj Al-Dhahab)
So you see what happened. The superintendent of prisons was flabbergasted and released the Imam immediately, organized an escort for him to take him to Madina.
Character and Virtues
Imam Musa Ibn Ja'afar (AS) was one of the illustrious Imams who God had set a paragon of moral excellence. Each member of this noble family possessed cardinal virtues. Naturally in some individuals a particular virtue is dominant and more conspicuous. The seventh Imam excelled in tolerance and forgiveness, so much so that he was entitled al-Kazim, the suppressor of anger. Never was he heard speaking roughly or harshly to anyone. Even in the most unpleasant situations, he was seen smiling bearing the pain gracefully. This was in accordance with the saying of his ancestor Imam Ali (AS) that the faithful keeps his grief confined in his heart with a smile on his face.
One State official of Madina was a persistent source of harassment to the Imam. He even used abusive language regarding Imam Ali (AS) but our 7th Imam always directed his followers not to retaliate in the same abusive manner. When his manner became too rude to be tolerated, Imam's followers sought permission from the Imam to retaliate against him. The Imam appeased them, promising to decide the matter in his own way.
Pacifying his followers, the Imam went to that man on his Farm and treated him with such noble benevolence that the man felt ashamed of his conduct and subsequently changed his attitude and altered his conduct. Explaining his policy to his followers, the Imam asked, "Was my behavior better than the methods you suggested?" They admitted that it certainly was. He thus carried out the instructions of his great ancestor Imam Ali (AS) which is recorded in Nehjul Balagha to subdue the enemy with benevolence since it is more effective than trying to defeat them with the same methods. No doubt this requires a correct judgment of your adversary's nature. Imam Ali (AS) has therefore warned not to use this policy with the vile and mean, or they will be encouraged to do more mischief.
To vanquish the enemy with goodness certainly requires the foresight the Imam possessed. Strictness is permissible only when the enemy's continuous vile conduct justifies retaliation or the use of force. If not, these dignified Nufus preferred to deal with that kind of person gently so as to have a valid pretext against the opponent and leave no ground for him to justify his aggression.
This was the noble method usually adopted by all members of Ahlulbayt. Imam Ali (AS) even on his death bed behaved liberally with Ibn Muljim who had dealt him a mortal blow only the day before. Imam Musa Ibn Ja'afar(AS) showered his generosity on many of his relatives even when he knew that some of them were envious of him and conspired with the ruler of the time Harun al-Rashid.
As to what may have led to his final imprisonment, we find that it is stated by Al-Fakhri that there were some of the relatives of Musa Ibn Ja'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 Madina, 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 Basra prison and taken to Baghdad. He was put in prison there under the watchful eye of the cruelest 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 Kazim (AS). 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.