Jafar Sadik had seven sons and four daughters. His first wife was Fatima. For the first 25 years he had only two sons by his first wife, Ismail and Abdullah and a daughter Umm Farwa. His second wife was Hamida, the mother of Musa Kazim and Muhammad. Besides, Abbas, Ali, Asma and Fatima were also the children of Jafar Sadik.
The butchery of Karbala and the sack of Medina had almost led to the closing of the lecture-room of the Imams in Medina. With the appearance of Jafar Sadik as the head of Muhammad's descedants, it acquired a new lease of life.

Abu Amr Muhammad al-Kashani writes in 'Marifat Akhbar ar-rijal' (p. 249) that once Jafar Sadik was pointed out by his disciples for wearing fine apparel, a variant of clothes from Marw, while his ancestors had worn rude and simple garments. He replied that his ancestors had lived in a time of scarcity, while he lived in a time of plenty, and that it was proper to wear the clothing of one's own time.

Extremely liberal and rationalistic in his teachings, Jafar Sadik was also a scholar, a poet, and a philosopher, well grounded in some of the foreign languages; he impressed a distinct philosophical character on the Medinite school. W.Ivanow (1886-1970) writes in 'Ismailis and Qarmatians' (JBBRAS, Bombay, 1940, p. 54) that, 'Jafar Sadik chiefly emphasized the tendency of moderation and sobriety in religious beliefs, i.e., exactly the qualities which strike us so much in early Ismailism.'

The Alids were totally disappointed while seeing the Abbasids taking power in the name of Ahl-al-Bait. The first task before Abbas as-Saffah therefore was to break the alliance with the Alids who were yet strong and could be dangerous. During his short rule of less than four years, he was kept fully occupied in meeting numerous insurrections and in ruthlessly killing those Alids who were suspected. The first to pay his life was Abu Salama. Abul Abbas died in 136/754, during which period, the Alids in Medina, disorganized by the frustration of their hopes, kept quiet. But when Abu Jafar Mansur, the brother of Abul Abbas as-Saffah assumed the caliphate, the Alids embittered by the usurpation of their rights by the house of Abbas, began to voice their complaints. An-Nafs az-Zakiyya, the son of Abdullah al- Mahd openly refused to take oath of allegiance to Mansur. The traditionalists circle of Medina supported him and upheld his cause. According to Tabari (3rd. vol., p. 200), 'Malik bin Anas declared that the oath sworn to the Abbasids was no longer binding as it had been taken under compulsion.'
Soon afterwards in 137/755, Abu Muslim was lured to Iraq and murdered. In 141/758, Mansur massacred a group of the Rawandiyya who besieged his palace. Caliph Mansur thus had to face the most threatening opposition from the Alids to the newly established authority of his house. He firstly concentrated his efforts on two basic points. The first was to justify the rights of his house on religious ground. The second was to gain for his caliphate the acceptance of the Muslims. The sources agree to mention that caliph Mansur also persecuted Imam Jafar Sadik many times, but the latter retained his equanimity.

The Abbasids had also adopted a very cruel policy towards the Umayyads, and many members of the family were ruthlessly executed. Some Umayyads, however, escaped and sought refuge among the nomadic tribes, one of them being Abdur Rehman (138-173/756- 788), the grandson of Hisham. He escaped to Rah, near Euphrates, where he began to prepare for the long journey to Africa, where few other Umayyad princes had already taken refuge. On 1st Shawal, 138/March 8, 756, he entered Archidona, the capital of Regio, where he was declared an amir. Hence, he became the king of the Umayyads in the southern districts of Spain.

Returning to the thread of our main narratives, it is recounted that Jafar Sadik died in 148/765 in Medina after the Imamate of 34 years and 7 months. Upon his death the Imamate devolved upon his elder son, Ismail.

Marwan, the Umayyad caliph was at that time advancing towards Kufa with a huge army. He encountered the army from Khorasan at a point on the greater Zab river, and the battle of Zab lasted for two days. It was closely contested struggle, and the day was turned when Marwan's horse ran away without its rider. He managed to escape, but was eventually discovered and killed.
So fell the last of the Umayyads in 132/750. The total duration of the Umayyad rule till the time when Abul Abbas assumed the power of the Abbasid rule was 90 years, 11 months and 13 days.

Meanwhile, things took a reverse turn for the Abbasid family. The army commanded by Abul Abbas and Abu Jafar Mansur, had come from Khorasan to Kufa, where they found the city decorated in black, the accepted colour of the Abbasids, and the people who crowded to the mosque also wore black clothes and black turbans with black banners planted in hands. Abu Salama led the prayers, after which he announced that Abu Muslim had now made it possible for the world of Islam to shake itself free from the Umayyads, and declared that it was to this end that he called upon them to recognize Abul Abbas, the brother of the murdered Ibrahim, as their rightful Imam and Caliph. Abul Abbas mounted the pulpit and made his inaugural speech, in which he named himself as as-Saffah (blood-shedder) and 'identified the glory of God with his own interest and those of his house. He named the Abbasids as the Ahl-al-Bait from whom uncleanliness was removed, and denined that the Alids were more worthy of the caliphate.' (vide Tabari, 3rd vol., p. 29). His speech was followed by a speech from his uncle, Daud bin Ali, who also emphasized that the rights of the Abbasids were legally inherited and there were but two legal caliphs in Islam: Ali bin Abu Talib and Abbas as-Saffah. He added that the caliphate would remain in the hands of the Abbasids until they passed it over to Isa bin Marium. (vide Tabari, 3rd vol., p. 31; Yaqubi, 2nd vol., p. 350 and Masudi, 3rd vol., p. 256). The excited crowd expressed their approval and gave their allegiance to Abul Abbas as the first caliph of the Abbasid caliphate in 132/750.

In Kufa, the local representive Abu Salama Hafs, the Kaysaniyan follower of Abu Hashim, known as Wazir-i Al-i Muhammad was very popular figure. Tabari (3rd vol., p. 27) writes that, 'When the news of the death of Ibrahim reached Kufa, Abu Salama on the suggestion and advice of some other Shias of Kufa, intended to establish the Imamate of Alids.' Accordingly, he wrote letters to Imam Jafar Sadik, Abdullah al- Mahd and Umar bin Ali Zayn al-Abidin, asking each one of them in turn to come to Kufa in person and he would support their claims of Imamate. The messenger was instructed first to contact Jafar Sadik, and only if he refused, then to go to Abdullah al-Mahd, and in case of his refusal, to Umar bin Ali Zayn al-Abidin. When the messenger presented the letter first to Jafar Sadik, the latter called for a lamp, burned the letter and said to the messenger, 'Tell your master what you have seen' (vide Ibn Tiqtaqa's 'al-Fakhri fi'l Adab as-Sultaniya', Cairo, 1966, p. 109). The messenger then came to Abdullah al-Mahd, who readily accepted the offer.

Abbas, the uncle of Holy Prophet had a son, Abdullah, who never tried to establish his own caliphate. Abdullah and his son, Ali bin Abdullah resided in Humayma. It was the latter's son, Muhammad bin Ali to have taken the charge of Kaysaniya sect from the dying Abu Hashim. Thus, the house of Abbas inherited the party and organisation of Abu Hashim along with his claims. Muhammad bin Ali led the Kaysaniya sect, and propagated in the name of Ahl-al-Bait, declaring that the caliph should be from Alid descent and the Umayyads had no right to rule. It was mere an ostensible slogan to procure wide supports of the Alids and nourish future political ambition. Muhammad bin Ali died before attaining his objective and handed on his claims to his son, Ibrahim. He began to dispatch emissaries, starting with Khorasan, where the bulk of the Kaysaniya faction resided.
In the meantime, the newly acclaimed Umayyad calipha Marwan sought to strike at the centre of the whole movement by arresting Ibrahim. He is said to have strangled him as Yaqubi writes, by having his head put into a bag of lime until he died. But Ibrahim had two brothers, Abul Abbas and Abu Jafar Mansur, both of whom escaped to Khorasan. And very soon these two brothers returned, supported by Abu Muslim's victorious troops, to lead the insurgents in their final struggle in the West. Their way had been prepared for them in Kufa by propaganda that had been carried on for more than twelve years.

Heretofore, we have examined that Mukhtar Thaqafi appeared in Kufa as a revenger of Hussain's blood after the event of Karbala. He failed to win support from Imam Zayn al-Abidin in his movement. He then turned to Ibn al-Hanafiya, whom he declared as an Imam and a promised Mahdi. Ibn al-Hanafiya did not repudiate Mukhtar's propaganda, and maintained a non-committal attitude, but his name became slogans for Mukhtar to gain public supports. Mukhtar was killed in 67/687, and the death of Ibn al-Hanafiya also took place in 81/700. Abu Hashim, the eldest son of Ibn al-Hanafiya however continued the mission originated by Mukhtar, and his followers then became known as Kaysaniyas. Various explanations are given to this name, but the Kaysan in question was almost certainly the man with the kunya Abu Amra, who was the most distinguished of the mawali supporting Mukhtar. The name was widely given to men of Alid sympathies during the later part of the Umayyad rule and was presumably a pejorative nickname first applied by opponents in order to discredit the group. Abu Hashim was poisoned by the Umayyad caliph Hisham, but before his death in 98/718, he quickly rushed to Humayma, and bequeathed his right to the caliphate and charge of the Kaysaniya sect to Muhammad bin Ali as he had no son.

Muhammad al-Bakir had four wives, the first being Umm Farwa bint Kassim bin Muhammad bin Abu Bakr, who gave birth of Jafar Sadik and Abdullah al-Fatah. The second wife, Umm Hakeem bint Asad bin Mughira Thaqafi had two sons, Ibrahim and Abdullah. The third wife was Layla, who gave birth of Ali and Zainab. While Umm Salma was the daughter being born by the fourth wife.
Ibn Hajar writes in his 'Sawaik'l Muhriqa' (p. 120) that, 'Imam Muhammad Bakir has disclosed the secrets of knowledge and wisdom and unfolded the principles of spiritual and religious guidance. Nobody can deny his exalted character, his God- given knowledge, his divinely-gifted wisdom and his obligation and gratitude towards spreading of knowledge. He was a sacred and highly talented spiritual leader and for this reason he was popularly titled al-Bakir which means the exponder of knowledge. Kind of heart, spotless in character, sacred by soul and noble by nature, the Imam devoted all his time in submission to God. It is beyond the power of a man to count the deep impression of knowledge and guidance left by the Imam on the hearts of the faithfuls. His sayings in devotion and abstinence, in knowledge and wisdom and in religious exercise and submission to God are so great in number that the volume of this book is quite insufficient to cover them all.'

Much has been recorded about Muhammad al-Bakir's person and extraordinary qualities. Once he said, 'The height of perfection is excellence in the understanding of the religion' and 'The scholar who derives benefit from his knowledge is better than seventy thousand devotees.' He strove to impress people by his extensive knowledge on religion as well as science. Himself a student of science had once said: 'Air contains a combustible energy, and if it is isolated, and comes in our hand in its purest form; it will cause a big combustible energy that can even melt away an iron.' Firstly, he indicates an existence of oxygen in air, which constitutes approximately 20% of the atmosphere. Oxygen was first isolated by a clergyman and chemist, Joseph Priestly (1733-1804) in 1774, and independently by Karl Scheele (1742-1786) at about the same period, and it was recognised as fire-air to be the promoter of combustion. But Lavoisier (1743-1794), a French chemist was the first to demonstrate the true nature of combution as an oxidation reaction and to give oxygen its modern name. Secondly, Muhammad al-Bakir indicates its power to melt an iron. There are some 40 variants of melting an iron. The oxy-Acetylene Gas is a dominant process for welding and melting an iron, and therefore, the oxyacetylene torch was invented in 1901 by Edmund Fouche.

In 106/725, caliph Hisham visited Mecca on pilgrimage when Muhammad al- Bakir was also in the city. Hisham found al-Bakir sitting among his followers, therefore, he sent one amazing question in the presence of al-Bakir, so that he might not give its answer and become discredited before his followers. Hisham's question was 'What will the people eat and drink on the day of judgement, till the time their reckoning is finished?' Imam replied that, 'There will be abundance of fruits and rivers on that place, from which they shall continue to avail till such time as their reckoning is finished.' Hisham had intended thereby to bring censure on al-Bakir in the open assembly. He was mighty gratified at this answer, thinking that it would provide him with an excuse for his designs. He therefore sent a counter-question that, 'Due to the fear of their accounts, how it is possible that the people will have the sense of eating.' Imam said, 'Go, and tell to Hisham that the sense of eating and drinking will be also among those people, who had been already cast into the hell. Does Hisham not read the Koranic verse, in which it is mentioned that, 'And shall call the inmates of the (hell) fire unto the inmates of the garden (of paradise), saying: Pour on us of the water or of what God hath provided you with; They shall say: Verily, God hath forbidden both to the infidels.' (7:50) On hearing this, Hisham was dumb founded and in his mind he had to admit the merits of al-Bakir.
Al-Bakir articulated the implication of the doctrine of taqiya in Shiism, and we may attribute the rudiments of its theory to him. But it was left to his son and successor, Jafar Sadik to give it a final form and make it an absolute condition of the faith.

Many leading jurists used to visit al-Bakir to discuss the legal problems. Among them were Muhammad bin Minkadir, Abu Hanifah an-Noman, Qatada bin Diama, Abdullah bin Mu'ammar and al-Laythi etc. He greatly emphasised also on the importance of knowledge and its romotion. Kulaini quotes in 'al-Kafi' (1st vol.,p. 89 and 104) that he said, 'Acquire knowledge and adorn it with forbearance and reverence. Be humble to those whom you give knowledge and also to those from you acquired it. Never be among the harsh tempered scholars. Lest you should forfeit your title because of your wrong and harsh demeanour.' He also said, 'The divine tax on knowledge is to teach it to God's creatures.'

Mirkhwand (d. 903/1498) writes in 'Rawzatus Safa' that, 'Neither the pen can write, nor the tongue can describe the merits and the traditions of al-Bakir.' Shibli Nomani writes in 'Sirat-i Numan' (Lahore, 1972, p. 28) that, 'Abu Hanifah sat for a long time at Imam Baqir's feet and acquired from him much valuable knowledge of fiqah and hadith not available anywhere else. Shiahs and Sunnis are agreed that Abu Hanifah derived much of his learning from Baqir.'

Muhammad al-Bakir died in 117/735, and was buried in the Baqi cemetery near his father's grave.

It is said that al-Bakir summed up the persecutions since the demise of Prophet Muhammad to his period in these words: 'Since the death of the Prophet, the Ahl-al-Bait have continued being humiliated, inflicted with pains, maltreated, put under trials, deprived of their rights, murdered, frightened. We did not find any security for our own blood and for our friends. The liars and deniers of our rights found a good pretext for their lies in order to be in the good books of their masters and bad judges and governors in every town. They told them fabricated traditions and reported of us those things which we never said nor had we done, in order to instigate people against us. The reign of Muawiya after the death of Hasan was prime period for such activities. In every town, our friends were killed; their hands and feet were amputated on mere doubt. Whoever mentioned our names with love was imprisoned, his property confiscated and his house pulled down. These calamities got severer and increased during the rule of Ubaidullah bin Ziyad, the murderer of Hussain. Then came Hijjaj. He killed them in cold blood and arrested them on doubt. So much so that the man who declared a pagan or kafir was dearer to him than the one who called himself a friend of Ali.' ('Ad-Darajat-ur-Rafiah fi Tabaqatil Imamiya min Shiah' by Sayed Ali Khan, cf. 'Shiite Encyclopaedia' by Hassan al-Amin, 1st vol., p. 29).