Whenever a Prophet addressed his people, calling on them to believe in God and in the Day of Judgement, they asked him to come up with miraculous evidence in support of his message. The Arabs of Makkah also demanded such miracles from the Prophet. God gave earlier Messengers such miraculous signs: the Prophet Moses transformed his staff into a fast moving serpent, and his hand changed colour when he put it on his chest; the Prophet Jesus cured the blind man and restored a dead man to life; and other Prophets were given miracles that suited their peoples and their standard of civilization. The Prophet Muhammad was given none of these because his message was applicable to all mankind in all generations. To produce a miracle seen by a limited group of people, large as it may be, at a particular time and in a particular place, does not fit with that status of his message and its universal applicability. The Prophet refers to this when he says:
"Every Prophet was given such miraculous signs as would make people believe. What I have been given is revelations bestowed on me by God. I hope that I will be the one with the largest following on the Day of Judgement." [Bukhari]
The messages given to earlier Messengers took different forms. Scriptures were given to Abraham, Moses and Jesus, and the psalms were given to David. However, these messages suffered changes and distortion that in some cases went in the opposite direction of what God wanted. People often ask why God allowed such distortion to creep into His messages. The reason is that God did not intend these messages to be the final ones. He has promised to preserve His final message intact and free of any distortion. As this final message addresses all mankind, in all generations, then it must be in the form of a book: it could not take any other form. Hence, we have the Quran, God's word that has remained, and will forever remain, available to all mankind in its original form, free from any distortion according to God's guarantee.
"Muhammad: His Character and Conduct" - Adil Salahi