Allah, Glory to be Him, provided every one of His prophets with books which He revealed to them. Those books or scriptures contained the tenets and fundamentals of religion as well as the instructions and commandments of Allah conveyed to various nations through His Messengers. The holy books were meant to be records of religion so that the various people and nations of the world might refer to them to know the ordinances and laws revealed by Allah and comply with them.
On the one hand, we are required to believe in all revealed books at large. On the other, we are required to believe in certain books which Allah told us He had revealed, namely:
1. The Qur'an, revealed to Muhammad;
2. The Gospel, revealed to Jesus;
3. The Psalms, revealed to David;
4. The Torah, revealed to Moses;
5. The Tablets, of Ibrahim (i.e., Abraham) and Moses (May peace and blessing of Allah be upon them).
Although books revealed to prophets before Muhammad (the last Messenger of Allah) were just temporary revelations each addressed to a particular tribe or nation, yet it is incumbent upon by Muslims to believe in them in general, and in the Qur'an on detailed basis in particular. The Qur'an is the final and comprehensive Scripture. It is the only book of Allah which has remained free from distortion and change, and has been transmitted to us whole in the most reliable ways and in its original text-a feature not enjoyed by any of the earlier books of revelation.