in the qur'an, allah states that he has brought about many miracles by means of the prophets. when the prophet musa (as) threw down his staff, for instance, it turned into a serpent, and when he smote the sea with that staff it divided into two, leaving a dry path down the middle. the prophet 'isa (as) came into the world without a father, and spoke while he was still in the cradle. another miracle is the way he was able to heal the sick… all these miracles were support and help given to them, in the sight of allah, to allow them to convince the people and lead them to believe in them.
allah supported the prophet muhammad (saas) by means of both the miracles in the qur'an and with information given him regarding the unknown. the prophet (saas) supplied details about events that would happen in the near and distant future. seeing these actually come to be is both a means of increasing the excitement of believers and of warming the hearts of unbelievers towards islam.
events that would have seemed impossible to happen in his own time, and that no one could even have imagined, which are now occurring one after the other, are clear evidence of the fact that the prophet (saas) was relating special knowledge.
we must make it clear that those who refuse to be guided to the true path will nevertheless still refuse to believe, despite the clear evidence and miracles of the prophet (saas) and the qur'an. allah reveals that fact in the qur'an:
they have sworn by allah with their most earnest oaths that if a sign comes to them they will believe in it. say: "the signs are in allah's control alone." what will make you realise that even if a sign did come, they would still not believe? (surat al-an'am: 109)