He was born in 745 CE in Medina to Ja'far al-Sadiq, the sixth Shia imam, who died in 765 without publicly designating a successor to save his heir from the wrath of the Abbasid caliphs.

The subsequent crisis of succession was eventually resolved in favor of al-Kazim, with a dissenting group, now known as the Isma'ilis, separating from the mainstream Shia.

To counter these restrictions, he established an underground network of local representatives to organize the affairs of his followers across the Abbasid empire and to collect their religious donations.

His final imprisonment, circa 795, ended with his death in 799 in a Baghdad prison, possibly poisoned at the instigation of the Abbasid caliph Harun al-Rashid.

Musa al-Kazim played a key role in eradicating extreme views and exaggerations (ghuluww) from Twelver thought.

[1] His father was Ja'far al-Sadiq, a descendant of Ali ibn Abi Talib and Fatima, who were the cousin and daughter of the Islamic prophet Muhammad, respectively.

[5] Ja'far al-Sadiq was widely accepted as the legitimate imam by the early Shia community, who rejected the ruling Umayyad caliphs as usurpers.

[1][14] Over time, he also established an underground network of representatives (wukala) to collect religious donations from his followers and organize their affairs.

[16] The Abbasids soon turned against their former allies,[17][18] and were generally hostile to the Shia imams, especially after the abortive 762–763 revolt of the Alid pretender Muhammad al-Nafs al-Zakiyya.

[19] Unlike his father, who often taught freely in Medina, al-Kazim was highly restricted by the caliphs,[14][20] and spent much of his adult life in the Abbasid prisons in Iraq.

[25][1] The resulting crisis of succession to al-Sadiq was ultimately resolved in favor of al-Kazim,[22] who spent the first ten years of his imamate under al-Mansur.

[33] The Shia imam was nevertheless accused of complicity by the Abbasid caliph al-Hadi, who was dissuaded from killing al-Kazim only by the intervention of the judge Abu Yusuf.

The vizier was reportedly threatened by the growing influence of Ja'far ibn Muhammad, who was entrusted with the caliph's son and heir, Amin.

[1] When Harun learned about this relatively comfortable conditions of al-Kazim, he gave Fadl a written order to kill the Shia imam.

[39][30] The caliph also publicly displayed the body of al-Kazim in Baghdad, perhaps to dispel the rumors that he had not died and would return as the Mahdi, the Messianic figure in Islam.

[1][14][45] A shrine has stood over the two graves since the time of the Buyid dynasty (r. 934–1062), but the present complex dates to the Safavid monarch Isma'il (r. 1501–1524), the Twelver ruler of Iran.

[24] The majority of his followers, the antecedents of the Twelvers, ultimately accepted the imamate of his son al-Kazim,[49][10] who also received the backing of some renowned students of al-Sadiq, including Hisham ibn al-Hakam and Mu'min al-Taq.

[60][9] For the Isma'ilis, the death of Isma'il in the lifetime of al-Sadiq did not annul his divine designation (nass), as that would have contradicted their belief in the omniscience of God.

[30] The Abbasid caliphs tightly controlled the activities of al-Kazim,[13] who consequently appointed a network of local representatives (wukala, sg.

[1][14] In particular, he might have allowed his companion Ali ibn Yaqtin to hold the vizierate to promote justice and social welfare,[79] or perhaps to save other Shias in times of danger.

[34] In line with the principle of taqiya, al-Kazim even instructed Ibn Yaqtin not to practice the Shia ablution (wudu') to avoid the suspicion of the Abbasid ruler.

[80] In another Shia report, al-Kazim saves Ibn Yaqtin by instructing him to withhold some goods destined for him, thus foiling a plot aimed at exposing their personal ties.

[91] The Waqifiyya included the Bushariyya, named after Muhammad ibn Bashir, the Kufan exaggerator (ghali) who regarded al-Kazim as divine and claimed to be his interim successor.

[1][97] More broadly, the term Waqifiyya or Waqifite is also applied to any Shia group who denied or hesitated over the death of a particular imam, thus refusing to recognize his successors.

[101] This also included the ability to communicate with animals, following the precedent of Surat al-naml, a chapter in the Quran, in which Solomon speaks with birds and ants.

Donaldson (d. 1976), these children were all sired with freed slaves (umm walads),[27] including Najma (or Tuktam) who bore al-Kazim his son and successor, Ali al-Rida.

[33][117] The shrines of some of the children of al-Kazim are sites of pilgrimage in Iran, including those of Fatima al-Ma'suma in the city of Qom,[33] Ali al-Rida in Mashhad, Husayn in Qazvin, and Ahmad in Shiraz.

faqih) who are believers (mu'min, i.e., Shia) are the citadels of Islam," has been reinterpreted in recent times to encourage an active social role for religious scholars.

[1][14] Among Sufi saints, Shaqiq ibn Ibrahim al-Balkhi (d. 809–810), for instance, regarded al-Kazim as a holy person (wali Allah, min al-abdal) and a devout worshipper,[14][128] while Ma'ruf al-Kharkhi (d. c. 815) and Bishr al-Hafi (d. 841) were affiliated with the imam.

[129] Musa al-Kazim is also a link in the Golden Chain (Silsilat al-dhahab), which is the initiatic line connecting the Sufis with the Islamic prophet Muhammad.