This example, then, further corroborates the first point. The syllogisms that philosophers employ in their sciences and declare to be universal are all buttressed by concrete instances. They possess nothing but what they have learned about the qualities of things that can be observed, and from that they analogize the unseen to the seen through the common element they treat as a universal. Were this procedure unsound, no one on earth would hold a single universal truth that embraces both what he has witnessed and what lies beyond his sight—even so obvious a statement as, “Bread satiates” or “Water quenches.” Sense perception affords him only particular cases; how, then, could he know that what is absent stands in the same relation as what is present except by this very method? A person may even deny a matter until he observes one instance of its kind; once he beholds that single case, he acknowledges the species and derives from it a general ruling.

For this reason the Exalted says:
“The people of Noah denied the messengers,”
“ʿĀd denied the messengers,”
“Thamūd denied the messengers.”
Each of these communities was visited by only one messenger, yet they rejected the whole genus of messengers; their denial was not of the individual as such. This contrasts with the Jews and Christians who rejected Muhammad—may God’s blessings and peace be upon him—for they did not repudiate the very idea of messengers; they rejected one specific messenger. The Arab idol-worshippers, however, had never known any messengers at all, so God argues with them in the Qur’an by establishing the very concept of prophethood.

Thus the Most High answers the objections of those who dispute the possibility of messengership, such as their saying, “Has God sent a human being as a messenger?” He replies, “We sent before you none but men to whom We revealed; so ask the People of the Reminder if you do not know.” In other words, this is a matter attested among the People of the Book—ask them whether the messengers who came to them were human or not.

Similarly, He says, “They say, ‘Why has an angel not been sent down to him?’ Had We sent down an angel, the matter would have been decided and they would have been granted no respite. And had We made him an angel, We would have made him appear as a man, and We would have confounded them in what they already confound themselves.” They would be unable to receive revelation from an angel in its own form; therefore, were We to send an angel, We would render him in human guise, and the matter would still be confused for them—they would say, “He is a man, and a man cannot be a messenger!” Such, too, was the case with the messengers before him, for the Almighty has said, “Do you marvel that a reminder has come to you from your Lord through a man …”