The Holy Imam Musa al-Kadhim is the Seventh Apostolic Imam. His epithet was Abu 'l-Hasan and his famous title was al-Kadhim. His matchless devotion and worship of God has also earned him the title of "al-'Abdu's-Salih" (virtuous slave of God). Generosity was synonymous with his name and no beggar ever returned from his door empty handed. Even after his death, he continued to be obliging and was generous to his devotees who came to his holy tomb with prayers and behests which were invariably granted by God. Thus, one of his additional titles is also "Babu'l-Hawaij" (the door to fulfilling needs).
Imam Musa al-Kadhim lived under the most crucial times in the regimes of the despotic `Abbasid kings who were marked for their tyrannical and cruel administration. He witnessed the reigns of al-Mansur ad-Dawaniqi, al-Mahdi and Harun ar-Rashid. al-Mansur and Harun ar-Rashid were the despotic kings who put a multitude of innocent descendants of the Holy Prophet to the sword.
His kind and generous attitude towards the people was such that he used to patronize and help the poor and destitute of Medina and provide for them cash, food, clothes and other necessities of sustenance secretly. It continued to be a riddle for the receivers of gifts throughout the Imam's lifetime as to who their benefactor was, but the secret was not revealed until after his death.
Time and circumstances did not permit the Holy Imam Musa al-Kadhim to establish institutions to impart religious knowledge to his followers as his father, Imam Ja'far as-Sadiq and his grandfather, Imam Muhammad al-Baqir had done. He was never allowed to address a congregation. He carried on his mission of preaching and guiding people quietly.
The Holy Imam was saved from the tyranny of al-Mansur because the king, being occupied with his project of constructing the new city of Baghdad, could not get time to turn towards victimizing the Imam. By 157 AH the city of Baghdad was built. This was soon followed by the death of its founder a year later. After al-Mansur, his son al-Mahdi ascended the throne. For a few years he remained indifferent towards the Imam. When in 164 AH he came to Medina and heard about the great reputation of the Imam, he could not resist his jealousy and the spark of his ancestral malice against the Ahlu'l-bayt was rekindled. He somehow managed to take the Imam along with him to Baghdad and got him imprisoned there. But after a year he realized his mistake and released the Imam from jail. al-Mahdi was succeeded by al-Hadi who lived only for a year. Now, in 170 AH, the most cruel and tyrannical king Harun ar-Rashid appeared at the head of the `Abbasid Empire. It was during his reign that the Holy Imam passed the greater part of his life in a miserable prison till he was poisoned.
Source: A Brief History of the Fourteen Infallibles (Ansariyan Publications)