“(We did so) lest a calamity might seize them because of the misdeeds they committed whereafter they would say: ‘Our Lord, why did You not send a Messenger to us that we follow Your revelation and become among those who believe!’ But when the Truth reached them from Us, they said: ‘Why was he not given that which was given to Moses?’ They said: ‘Both are magic, each supporting the other!’”
(Al Qur’ān – 28:47-48)
The Qur’ān mentions this on several occasions as the reason behind the raising of the Prophets. It would be incorrect, however, to deduce from this that there must always be a Prophet in every land. As long as the means for the correct transmission of a Prophet’s Message are available, there is no need to raise a new Prophet. Not unless it is felt that something needs to be added to that previous Message, or that an altogether new Message needs to be delivered.
There were times, however, when the teachings of the Prophets disappeared altogether from the scene or became exceedingly distorted, lost in a heap of error and falsehood. On such occasions they ceased to have the potential to guide people. In such times, people might argue that since no one has explained to them the distinction between Truth and falsehood, it was not possible for them to be directed to the Right Path. It was on such occasions that God sent His Prophets to mitigate this excuse; thereafter, if anyone follows the wrong path, he will be held responsible for his wrong choice.