Some of these books were...
Some of these books were, however, descended to the Prophets themselves (these are not more than a few) but others were those left behind by previous Prophets, either distorted or misunderstood, which the Prophets after them undertook to correct or interpret.
As an example, after Moses, the Torah was misunderstood by some, even mingled with polytheistic ideas, and thus such Prophets as Salomon, David, etc., who succeeded Moses, tried to provide the people with the true meanings and concepts of this Book. This is also true with the Qur’an.
That is to say that there is a considerable difference between our understanding of the Qur’anic teachings and that of the past generations (taking into account the fact that the text of the Qur’an and its concepts and realities have remained untouched). In the past, these teachings were considerably misunderstood because distorted matters and wrong ways of thinking obsessed the people's minds and prevented them from the correct understanding of the Qur’an.
But today, the Qur’an is correctly understood and it is likely that in the future some Qur’anic realities be unveiled that we do not perceive today (According to some traditions, when eventually Imam-Mahdi reappears, he will introduce a new religion-the true Islam. Today, some Sunni and non-Sunni jurists have announced that the religion, which people follow in Iran, is not Islam.
They tell the truth because this is not that Islam in which they believe-that distorted Islam which contains idolatry, polytheistic and anti-Islamic ' values. Our Islam is different from that Islam whose mosque does the President of America inaugurate and whose Qur’an does the Shah of Iran print. There is a great and changing distance between these two forms of Islam).
The Books of the Prophets were, however, sufficient as long as they remained untouched, their concepts were rightly expounded and they were correctly interpreted. In the case of Moses, for example, his Book remained perfect and undistorted after he died, during the time when the Children of Israel were in a state of bewilderment and sought to reach Jerusalem, and guaranteed the victory of Israelites as well as the establishment of the Mosaic community.
(This community, which was powerful and enjoyed a government, came into being after Moses' death.