Justin Martyr

There existed, long before this time, certain men more ancient than all those who are esteemed philosophers, both righteous and beloved by God, who spoke by the Divine Spirit, and foretold events which would take place, and which are now taking place. They are called prophets. These alone both saw and announced the truth to men, neither reverencing nor fearing any man, not influenced by a desire for glory, but speaking those things alone which they saw and which they heard, being filled with the Holy Spirit. Their writings are still extant, and he who has read them is very much helped in his knowledge of the beginning and end of things, and of those matters which the philosopher ought to know, provided he has believed them. For they did not use demonstration in their treatises, seeing that they were witnesses to the truth above all demonstration, and worthy of belief; and those events which have happened, and those which are happening, compel you to assent to the utterances made by them, although, indeed, they were entitled to credit on account of the miracles which they performed, since they both glorified the Creator, the God and Father of all things, and proclaimed His Son, the Christ [sent] by Him: which, indeed, the false prophets, who are filled with the lying unclean spirit, neither have done nor do, but venture to work certain wonderful deeds for the purpose of astonishing men, and glorify the spirits and demons of error.