Each of them has a right to be heard and considered. But as a yardstick external to and outside of whatever is to be measured is needed, so there must be some permanent tests available to all men, all civilizations, and all ages, by which they can decide whether any of these claimants, or all of them, are justified in their claims. Reason dictates that if any one of these men actually came from God, the least thing that God could do to support His claim would be to pre-announce His coming.
Automobile manufacturers tell their customers when to expect a new model.
If God sent anyone from Himself, or if He came Himself with a vitally important message for all men, it would seem reasonable that He would first let men know when His messenger was coming, where He would be born, where He would live, the doctrine He would teach, the enemies He would make, the program He would adopt for the future, and the manner of His death. By the extent to which the messenger conformed with these announcements, one could judge the validity of his claims. In such cases there would be no objective, historical way of testing the messenger. We would have only his word for it, and of course he could be wrong. With this test one can evaluate the claimants.