But there is no futility in creation. In other words, ever since he has inhabited the earth, human has had the wish to lead a social life filled with happiness in its true sense and has striven toward this end. Therefore, by the reason of inner necessity and determination, the future will see a day when human society will be replete with justice, when all will live in peace and tranquillity, and when human beings will be fully possessed of virtue and perfection. The establishment of such a condition will occur through human hands but with Divine Assistance. These religions have given glad tidings of his coming, although there are naturally minor differences in detail that can be discerned when these teachings are compared carefully.
Every religion has a different attachment to it, however.
Thus, the saviors of all these religions who are all expected to come at the end of the time, are manifested in one individual, since the foundation of such belief is established by all. The attachments of different religions can be reconciled on their own tendencies, and thus rejected. The fact remains that the teachings of the previous religions have been under a long alteration process, and only Islam has been guaranteed its survival. There are numerous traditions cited in the Sunni and the Shi'i sources from the Holy Prophet concerning the appearance of the Mahdi, such as that he is of the progeny of the Prophet and that his appearance will enable human society to reach true perfection and the full realization of spiritual life. Even if there remain from the life of the world but a single day, Allah will expand that day until he becomes manifest and fills the world with justice in the same way that it had been filled with injustice.