Islam tells us that all religions revealed by God to His messengers brought true guidance from Him and, therefore, were one and the same. Therefore, Islam is not a recent religion. It is the same religion sent by God through His Prophets since the beginning of human history. So we can say that God had sent all the previously revealed books so that man might be informed of the nature of his life. The Quran, the last of the revealed books, endorses all the revealed books, which preceded it. But this endorsement applies to them only in their original, pristine versions. The religious scriptures preceding the Quran were- as is claimed by their followers- divine in origin. But from the point of view of academic authenticity they have lost their original credibility. This is due to alteration, deletion and interpolation in them. This happened because none of the followers of the prophets were able to preserve the revealed books and teachings of their prophets. Either these religions survived in a distorted form, or they vanished without leaving any trace. In contrast to this, the Quran has been preserved in its entirety as can be seen from the fact that there is not an iota of a difference between any two copies of the Quran - either hand written or printed.
Therefore, the Quran, as revealed to the final Prophet Muhammad, is the only authentic version of God's message to mankind in the world today. We can understand this with the help of the following example.
In 1509 Michelangelo (1475-1564), painter, sculptor, architect and poet was commissioned by Pope Julian to design and paint the frescoes for the Sistine Chapel in the Vatican. The project was completed in 1512. In the 450 years that have elapsed since then, the original colours used by Michelangelo have become considerably subdued and, therefore, distorted. One reason for this was that a coating of animal glue was spread over the surface of the fresco in the 17th century to keep the plaster from flaking. This glue then collected centuries of soot from the torches used to illuminate the chapel before the advent of electricity.
Under Pope John Paul II, the Vatican has ordered restoration of the fresco. At the beginning of 1986 the first results of the cleaning work were displayed to the public. Renovation has revealed some startling things about Michelangelo's original work. The master was previously believed to have used subdued, twilight colours, but it now appears that the colours he used were so vibrant that softer lighting will be needed when the cleaning is finished in 1988. Art historians now have to revise their whole concept of the Florentine school, which Michelangelo represented, for the Florentines have been considered masters of design, but not of colour. George Armstrong writes in The Guardian Weekly (February 16, 1986) that the axiom of Tintoretto (1518-1594) "draw like Michelangelo, paint like Titian"- "has been thrown off balance by the Sistine's restored colours." The renovation, Armstrong says, has revealed "Michelangelo in a new light."
In very much the same way, the nature of true religion has become distorted over the centuries. However, unlike in the above example we are not in a position to look at the original scriptures of other religions, as they have been lost in history.
This happened as originally religion is revealed by God and taught in its pure form by the prophets. Then, when it falls into the hands of ordinary men, they corrupt its true message, making it conform to their own desires. Whereas religion had originally been based on belief in the hereafter, it later became an instrument for the acquisition of worldly wealth and power. True faith, as painted by the prophets, springs from the heart, but religion in its corrupted form becomes a mere accumulation of rites and ceremonies, devoid of any true spirit. Religion in its pristine form breeds humility in its followers, fostering human unity; but when religion becomes distorted, it becomes a source of pride, with one group using it to assert their superiority over another.
When this happens, it means that grime and dust have collected on the face of true religion. Its true colours have become distorted and it is in need of restoration to its original form. When the renovation is completed, it will be revealed that religion is something quite different from what men have made it out to be. Theologians will be exposed as misleading in their interpretations, just as the public has been misguided in its opinions.
Another thing that needs to be understood is that Islam is not an exception to this rule. A veil of interpretation has also covered the original Islamic ideology that was revealed to Prophet Muhammad. However the only difference is that while in the case of other religions, the very text of their scriptures was changed; in the case of Islam, the text of the Quran and the Sunnah is preserved, a veil of interpretation has formed over it through their commentaries and interpretations.