In the history of Islamic legal thought, al-Juwaini's al-Ghiyathi is a unique work, because he devotes himself in its last chapter to dealing with the possibility of Mappo (borrowed from a Buddhist concept), the era of extinction of the Shari'a, not in an eschatological way but in a juristical way.
He says that the knowledge of the fundamentals of Shari'a will be lost among people after the disappearance of its legal authorities, i. e., mujtahids and transmitters of madhhabs, which will occur after the disappearance of the political authorities, i. e., caliphs and sultans.
According to his understanding, the extinction of the knowledge will happen not because of the lack and decrease of books, but because of the increase of hairsplitting debates and pedantic disputes which occupy so much the minds of people and students as to make them tired at last.
al-Juwaini compares Muslims in the era of extinction of the Shari'a with people whom the message of Islam has not reached. He concludes that, besides the beliefs in the unity of God and the prophethood of Muhammad, Muslim's sole obligation in such an era is to make himself ready for observance of the prescriptions of Shari'a, hoping to get to know them someday. Because there is no obligation without receiving the divine commandments according to the Ash'ari school to which al-Juwaini belongs.
In his opinion the details of the Shari'a can not be understood without guidance of its authorities. So the utmost which can be hoped in case the legal authorities as well as the political authorities have disappeared, is that individual muslims reconstruct the fundamentals of the Shari'a from the remaining writings on the subject and apply the fundamentals to their own situations.
