There are many who, although of no name, with the greatest facility and on the slightest occasion, whether within or without temples, assume the motions and gestures of inspired persons; while others do it in cities or among armies, for the purpose of attracting attention and exciting surprise. These are accustomed to say, each for himself, ‘I am God; I am the Son of God; or, I am the Divine Spirit; I have come because the world is perishing, and you, O men, are perishing for your iniquities. But I wish to save you, and you shall see me returning again with heavenly power. Blessed is he who now does me homage. On all the rest I will send down eternal fire, both on cities and on countries. And those who know not the punishments which await them shall repent and grieve in vain; while those who are faithful to me I will preserve eternally.’ … To these promises are added strange, fanatical, and quite unintelligible words, of which no rational person can find the meaning: for so dark are they, as to have no meaning at all; but they give occasion to every fool or impostor to apply them to suit his own purposes. (Origen, Contra Celsum 7.9)
I’m a bit confused, though, because Aslan left a lot out. As you can see, Celsus was speaking in the present tense, and as the immediately preceding discussion by Origen (who is our sole source for Celsus’ lost work) makes clear, this was meant to be the time of writing: “Celsus promises to give an account of the manner in which prophecies are delivered in Phoenicia and Palestine, speaking as though it were a matter with which he had a full and personal acquaintance” (7.8). This would have been around 177 CE, when Celsus wrote, almost 150 years after Jesus.
Origen makes another important point:
He adds, with the view of casting a slight upon the ancient [Jewish] prophets, that “they prophesied in the same way as we find them still doing among the inhabitants of Phoenicia and Palestine.” But he does not tell us whether he refers to persons who are of different principles from those of the Jews and Christians, or to persons whose prophecies are of the same character as those of the Jewish prophets. (7.8)
Therefore, Aslan’s statement is technically wrong on essentially every count: Celsus was not referring to Galilee specifically but rather the entire eastern Mediterranean coast; he was speaking of the second century and not the first; the prophets in question may or may not have been Jewish; and said holy men were not wandering hither and yon alone but rather were preaching in temples, in cities, and in the military. The cute anecdote about the Greek guy reporting a wave of babbling prophets marching around in the time of Jesus isn’t what the original text actually says.
Now, don’t get me wrong: There were plenty of people claiming divine status in the era of Jesus. Simon of Peraea, Athronges, Menahem ben Judah, Simon Magus, and Dositheos the Samaritan all claimed to be the Messiah in the century or so around Christ, for example. Further, the Roman Empire was lousy with itinerant preachers and teachers, some of whom would have preached the Jewish doctrine of the End of Days, such as that given in Malachi 4:1: “‘Surely the day is coming; it will burn like a furnace. All the arrogant and every evildoer will be stubble, and the day that is coming will set them on fire,’ says the Lord Almighty.” Among the pagans, the same type of figure prevailed, including the famous Apollonius of Tyana, and other wandering philosophers and wonder-workers.
So, Aslan’s broader point is right, if incomplete, though the text he uses to support it isn’t quite what he made it seem. The good news is that he goes on to clarify and correct most of the issues in the succeeding paragraphs, though so far as I have read, he doesn’t get back to Celsus.