And now, since we have touched upon the subject of the prophets, what we are about to advance will be useful not only to the Jews, who believe that they spoke by divine inspiration, but also to the more candid among the Greeks. To these we say that we must necessarily admit that the Jews had prophets, if they were to be kept together under that system of law which had been given them, and were to believe in the Creator of the world, as they had learned, and to be without pretexts, so far as the law was concerned, for apostatizing to the polytheism of the heathen.
And we establish this necessity in the following manner. “For the nations,” as it is written in the law of the Jews itself, “shall hearken unto observers of times, and diviners;” but to that people it is said: “But as for you, the Lord your God has not suffered you so to do.” And to this is subjoined the promise: “A prophet shall the Lord your God raise up unto you from among your brethren.” Since, therefore, the heathen employ modes of divination either by oracles or by omens, or by birds, or by ventriloquists, or by those who profess the art of sacrifice, or by Chaldean genealogists— all which practices were forbidden to the Jews— this people, if they had no means of attaining a knowledge of futurity, being led by the passion common to humanity of ascertaining the future would have despised their own prophets, as not having in them any particle of divinity; and would not have accepted any prophet after Moses, nor committed their words to writing, but would have spontaneously betaken themselves to the divining usages of the heathen, or attempted to establish some such practices among themselves.
There is therefore no absurdity in their prophets having uttered predictions even about events of no importance, to soothe those who desire such things, as when Samuel prophesies regarding three she-asses which were lost, or when mention is made in the third book of Kings respecting the sickness of a king's son. And why should not those who desired to obtain auguries from idols be severely rebuked by the administrators of the law among the Jews?— as Elijah is found rebuking Ahaziah, and saying, “Is it because there is not a God in Israel that you go to inquire of Baalzebub, god of Ekron?”
Source: Against Celsus (New Advent)