Designation After the death of al-Sadiq in 765, his following became fractured, for he did not publicly designate a successor to save his heir from the Abbasids' wrath. The majority of his followers, the antecedents of the Twelvers, ultimately accepted the imamate of his son al-Kazim, who also received the backing of some renowned students of al-Sadiq, including
Hisham ibn al-Hakam and
Mu'min al-Taq. However, instead of al-Kazim, many expected the next imam to be his elder half-brother,
Isma'il ibn Ja'far, who predeceased his father. These were the antecedents of the
Isma'ilis, some of whom waited for Isma'il to return as the Mahdi and the others instead accepted the imamate of his son
Muhammad ibn Isma'il. When the latter died, some expected him to return as the Mahdi and others followed a line of imams who claimed descent from him. Even though the Isma'ilis were active against the Abbasids, they were of marginal importance until their political success much later: The
Fatimid Caliphate was established in Egypt at the turn of the tenth century and the
Qarmatians rose to power in
Bahrain in the late ninth century. Their relations with the mainstream Shia were apparently tense at the time, as some have implicated them in the arrest of al-Kazim and the murder of some of his followers. Isma'ilis believe that Isma'il was the designated successor, and this appears to be the general consensus of the early Shia sources as well. For the Isma'ilis, the death of Isma'il in the lifetime of al-Sadiq did not annul his divine designation (), as that would have contradicted their belief in the omniscience of God. By contrast, the early Twelvers explained any such changes in the divine will be through , a notion similar to abrogation () in the
Quran. Later Twelvers, such as al-Mufid, altogether rejected the claim that Isma'il was the designated successor of al-Sadiq. Historical evidence indeed suggests ties between Isma'il and radical Shias, of whom the quiescent al-Sadiq did not approve. Twelvers instead cite the qualifications of al-Kazim to support his fitness for the imamate after al-Sadiq. While the Twelvers and the Isma'ilis are the two sects that have survived, there were also additional branches that emerged after the death of al-Sadiq: After the death of al-Sadiq, some waited for his return as the Mahdi, but perhaps the majority of his followers initially accepted the imamate of his eldest surviving son, Abd-Allah al-Aftah. This group became known as the
Fathites. Abd-Allah apparently lacked the scholarly prerequisites for the imamate and died a few months later without a male heir. His followers then mostly turned to al-Kazim, although for some time they still counted al-Aftah as their seventh imam. Some other followers of al-Sadiq turned to Musa's younger brother, al-Dibaj, who staged an unsuccessful revolt against the Abbasids in 815816. Over all, it appears that many of those who had split off after the death of al-Sadiq eventually joined al-Kazim later.
Representatives , with inserts on the vicinities of
Baghdad and
Samarra, during the Abbasid period The Abbasid caliphs tightly controlled the activities of al-Kazim, who consequently appointed a network of local representatives (, ) to organize the affairs of the Shia and collect their religious dues, particularly
Khums (). Extending throughout the Abbasid empire, this underground network was likely established by al-Kazim, while there is also some evidence that an earlier network might have existed under his predecessor, al-Sadiq. During the imamate of al-Kazim, new Shia centers were also established in the
Maghreb and Egypt. It appears that al-Kazim permitted cooperation with the Abbasids so long as it furthered the Shia cause. In particular, he might have allowed his companion
Ali ibn Yaqteen to hold the vizierate to promote justice and social welfare, or perhaps to save other Shias in times of danger. In line with the principle of , al-Kazim even instructed Ibn Yaqtin not to practice the Shia ablution () to avoid the suspicion of the Abbasid ruler. 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. Ibn Yaqtin was nevertheless finally arrested, as part of the same campaign of arrests that led to the imprisonment and death of al-Kazim. He later died in prison. Historically, whether Ibn Yaqtin attained the vizierate office and for long enough to make any difference is uncertain. Some other Abbasid officials whose loyalty rested with al-Kazim were Abbas ibn Ja'far al-Ash'ath, governor of
Khorasan, and Waddah (or Wadih), who was an official of the postal service () in Egypt.
Succession After the death of al-Kazim in 799, most Shias acknowledged his son,
Ali al-Rida, as their imam. These Shias were the antecedents of the Twelvers, known at the time as the Qat'iyya because they confirmed the death of al-Kazim. By contrast, some followers of al-Kazim waited for his return as the Mahdi, citing a
hadith ascribed to al-Sadiq to the effect that the seventh imam would be the Mahdi; these became known as the
Waqifite Shia (). Many of the Waqifiyya later returned to the mainstream of Shia, declaring al-Rida and his descendants as the lieutenants of al-Kazim. The Waqifite Shia sect and its beliefs eventually disappeared, beginning in the ninth century. The Waqifite Shia included the Bushariyya, named after Muhammad ibn Bashir, the
Kufa exaggerator () who regarded al-Kazim as divine and claimed to be his interim successor. Ibn Bashir was later charged with heresy and executed by order of the caliph. The formation of the Waqifite Shia may have had a financial dimension, as some representatives of al-Kazim probably declared him the last imam just to avoid returning what was entrusted to them during the lifetime of al-Kazim. These rogue representatives included Mansur ibn Yunus al-Qurayshi, Ali ibn Abi Ḥamza al-Bata'ini, Ziyad ibn Marwan al-Qandi, Uthman ibn Isa al-Amiri al-Ruasi (Ruwasi), and Hayyan al-Sarragh, although al-Ruasi may have later turned possessions over to al-Rida. More broadly, the term Waqifite Shia is also applied to any Shia group who denied or hesitated over the death of a particular imam, thus refusing to recognise his successors. The imamate of Ali al-Rida was not challenged by any of his brothers, even though some of them revolted against the Abbasids, including Ahmad ibn Musa.
Often viewed as evidence of his divine favor, various nonprophetic miracles (, ) have been attributed to al-Kazim in Shia sources. Therein, he is considered knowledgeable of all languages, and this ability in Shia sources is not specific to al-Kazim. Indeed, a hadith attributed to al-Kazim counts this ability as a sign of the true imam. This also included the ability to communicate with animals, following the precedent of
An-Naml, a chapter in the
Quran, in which
Solomon speaks with birds and ants. Musa al-Kazim is thus said to have prayed for a wild beast to ease the birthing pains of its partner. By other accounts, Musa spoke in his cradle, revived a dead tree with his touch, and brought back to life the dead farm animal of a poor family. By another account, al-Kazim showed to a disciple the spirit of al-Sadiq, who had died some years earlier, seated in the entryway to his house.
Ghulat Musa al-Kazim and his father al-Sadiq successfully rooted out the belief in the imam's divinity from mainstream Shia thought, as evidenced by its absence in later mainstream Shia writings. Nevertheless, there remained at the time groups with extreme views () embedded within mainstream Shia. These
Ghulat () continued to believe in the divinity of the Shia imams. For instance, the Mufawwida believed that God had delegated () the affairs of this world to the prophet and the Shia imams. Such beliefs were also championed by
al-Mufaddal ibn Umar al-Ju'fi, a financial agent of al-Kazim. However modern Shi'i scholars have accepted Mufaddal as a pious companion, and the works attributed to him false. There is no evidence that any of the Shia imams personally subscribed to these extremist views.
Redemptive suffering By some Shia accounts, al-Kazim died for the sins of his followers. This is explained in a tradition attributed to him, "God became wrathful with the Shia, so he made me choose between them or myself and I shielded them, by God, with my soul". This tradition may also suggest al-Kazim's premonition about his own death. These sins may have been disloyalty (to the imam) and abandoning (religious dissimulation), according to the Twelver traditionist
Muhammad ibn Ya'qub al-Kulayni (), who adds that the latter sin revealed the activities of al-Kazim and led to his imprisonment. Harun indeed carried out a campaign of arrests in 795 to decimate the underground network of local Shia representatives (), which may have led to the final arrest of al-Kazim. == Descendants ==