It is worth mentioning that the Sunni historians had no basic idea of the Shiite concept of Imamate and arrayed hostility with the Ismailis in the light of their own sense of propriety. They championed in dressing up the baseless stories in their notion, and then used it a tool to defile Ismailism in aggressive and hyperbolic words. Under such derogatory attitude, Muhammad bin Ismail is accused of claiming the prophethood and abolishing the Shariah of the Prophet.
The institution of the Imamate is a cornerstone and paramount position in Ismaili tariqah, and according to their theory, the seven millennial periods (adwar'i azam) form a part of a great cycle of 360,000 years. At its end, during the last period of 7000 years, there were six natiqs (speakers, pronouncers or law-givers), viz. Adam, Noah, Abraham, Moses, Jesus and Muhammad, the last Prophet. They are the seven law-givers. Each great period is started by the introduction of a new religion. This religion, exercising great influence upon mankind at the outset, but lost its original force with the passage of time. It is ultimately replaced by a new system to retain its originality and make it forceful then onwards. Each natiq lays down the Shariah for his period, and appoints an asas (base, foundation or executor). The asas lays the foundation of hidden knowledge (ilm al-batin), who is also called wasi, organizing the dissemination of the hidden knowledge among the faithfuls only. The asas is followed by a chain of Imams, who stimulate the mission on the basis of hidden teachings. The period (dawr) of one natiq comprises six ones and the seventh one becomes another natiq, who either proclaims another Shariah setting aside the earlier one, or cancelling (tatil al-shariah) its manifestation, and gives it a new interpretation on the ground of hidden secrets (asrar'i batin). The Prophet Muhammad was preceded by five natiqs, each natiq had cancelled his predecessor's Shariah. With this cycle, the Prophet stands as the sixth natiq who appointed his son-in-law Ali as his wasi, and there followed after him six Imams, bringing the Prophet's period (dawr) to a close. The seventh Imam, Muhammad bin Ismail was the seventh natiq in the new heptad. Muhammad Bakir Majlisi quotes a Hadith in his "Biharu'l Anwar" (13th vol., p. 156) that, "The next expected (natiq) Imam would be "the son of six" (ibn sitta), means the next natiq would be preceded by six Imams." Since there was no Shariahafter the Prophet, Muhammad bin Ismail was not to announce a new religious law. Instead, he would reveal the esoteric truths concealed behind all the preceding messages. He abrogated the adulterated parts of the Shariah by explaining the hidden meaning of the true Shariah and revealing its purpose. The Islamic Shariah had lost much of its pristine purity, and many unhealthy practices crept into the religion, therefore, the tawil was applied to protect its dynamic force.
Abrogation of the Shariah, therefore, by every seventh natiq encompasses the meaning of the law only, not its exoteric or practical and ritualistic aspects. The Prophet was ar-Rasulu'n-Natiq, whereas Muhammad bin Ismail was al-Imamu'n-Natiq. The former was the natiq in the capacity of the Prophethood, and the latter was the natiq in the role of Imamate. Thus, Muhammad bin Ismail had never repudiated or suspended the Shariah for his followers. Arif Tamir writes in "al-Qaramita" (pp. 86-87) that, "The Imamate of Muhammad bin Ismail was the beginning of a new era in the history of the Ismaili movement. We go even further to say that he came with some new teachings, setting aside some exoteric teachings which preceded. He was in fact the first Imam to have done away with the trouble of manifestation and gave call for tawil and esoteric meaning, and for spreading his mission, he relied on his hujjat and great dai, Maymun al-Qaddah." Idris Imaduddin (d. 872/1468) writes in "Zahru'l-ma'ani" that, "Muhammad bin Ismail was named the seventh natiq, because he rose to preach by the command of God, incorporating in himself all the virtues which are to be crowned in him. He is neither the Revealer of the final religion, nor the Apostle of God, but he is in a class by himself, of a unique rank."
It must be noted that the period of Muhammad bin Ismail was a turning point in the history of the Ismaili mission. The Abbasids revolution had been consolidated, and the Iranian influence in particular and Greek influence in general were being applied in the intellectual field. In a century that followed, the wave of Muslim conquest reached upto Samarkand, beyond the Oxus. With the extension of Muslim territory, there cropped up a number of new problems neither contained in Koran, nor anticipated by the Prophet. Hundreds of schools of jurisprudence appeared to mould the Muslim system of laws, but none could crystallize into definite system, acceptable by all. "Some five hundred schools of jurisprudence" writes Adam Mez in "The Renaissance of Islam" (London, 1937, p. 212), "are said to have disappeared at or about the beginning of the 3rd/9th century."
The Schools of Law represented by Abu Hanifah (d. 150/767), Malik bin Anas (d. 179/795), al-Shafi (d. 204/819) and Ahmad bin Hanbal (d. 241/855) also emerged prominently in this period. The major collections of Hadiths also were done mainly by Bukhari (d. 256/870) and Muslim bin al-Hajjaj (d. 261/875).
The problem however was to find a correct balance among all these developments when the Islamic world was undergoing radical changes. Islam had to keep pace with, and adjust to, the fast changing world and the growing of new trend. Muhammad bin Ismail had to impart the true Islamic teachings through tawil (the allegorical interpretation) based on reason to his followers. It was thus absolutely a false propaganda of the historians that Muhammad bin Ismail - he being the seventh natiq had claimed for his apostleship or cancelled the Shariah of the Prophet. P.J. Vatikiotis writes in "The Fatimid Theory of State" (Lahore, 1957, p. 90) that, "Abrogation of the Shariahby every Seventh natiq, as for example Muhammad b. Ismail, encompasses the meaning of the law only, not its zahir or practical and ritualistic aspect. Muhammad b. Ismail did not abolish anything of the formal worship and law of the Shariah; on the contrary, he strengthened it, and ordered everyone to act according to it. What Imam al-Muizz meant by the expression al-shariah uttilat, or the Shariah of Muhammad was purified by his mission, refers to his explaining its meaning and clarifying its hidden points. Tatil of Shariah, then, means its purification through tawil. A revelation of the external truths behind the Shariah to the closest initiates in the dawa constitutes Fatimid abrogation of law. It is not an abrogation that overthrows accepted legal ritual in the Quran, but rather the reconciliation of such law with religious philosophy."
It should also be known that the mis-interpretation of the theory of Muhammad bin Ismail as the Seventh natiq by the Sunni historians had engendered the coinage of the name "Seveners" (sabiya) for the Ismailis, which is a glaring instance, sounding their misconception in the Ismaili belief of Imamate. The Muslim knowledge of the Ismailis in the field of tawil had not progressed much beyond what they had transmitted on the subject. They knew little and broadcast more, and the field therefore continued to be dominated by the fanciful impressions and fictitious hodgepodge.