But, that we might attain an ampler and more authoritative knowledge at once of Himself, and of His counsels and will, God has added a written revelation for the behoof of every one whose heart is set on seeking Him, that seeking he may find, and finding believe, and believing obey. For from the first He sent messengers into the world, -- men whose stainless righteousness made them worthy to know the Most High, and to reveal Him, -- men abundantly endowed with the Holy Spirit, that they might proclaim that there is one God only who made all things, who formed man from the dust of the ground (for He is the true Prometheus who gave order to the world by arranging the seasons and their course), -- these have further set before us the proofs He has given of His majesty in His judgments by floods and fires, the rules appointed by Him for securing His favour, as well as the retribution in store for the ignoring, forsaking and keeping them, as being about at the end of all to adjudge His worshippers to everlasting life, and the wicked to the doom of fire at once without ending and without break, raising up again all the dead from the beginning, reforming and renewing them with the object of awarding either recompense. Once these things were with us, too, the theme of ridicule. We are of your stock and nature: men are made, not born, Christians. The preachers of whom we have spoken are called prophets, from the office which belongs to them of predicting the future. Their words, as well as the miracles which they performed, that men might have faith in their divine authority, we have still in the literary treasures they have left, and which are open to all. Ptolemy, surnamed Philadelphus, the most learned of his race, a man of vast acquaintance with all literature, emulating, I imagine, the book enthusiasm of Pisistratus, among other remains of the past which either their antiquity or something of peculiar interest made famous, at the suggestion of Demetrius Phalereus, who was renowned above all grammarians of his time, and to whom he had committed the management of these things, applied to the Jews for their writings -- I mean the writings peculiar to them and in their tongue, which they alone possessed, for from themselves, as a people dear to God for their fathers' sake, their prophets had ever sprung, and to them they had ever spoken. Now in ancient times the people we call Jews bare the name of Hebrews, and so both their writings and their speech were Hebrew. But that the understanding of their books might not be wanting, this also the Jews supplied to Ptolemy; for they gave him seventy-two interpreters -- men whom the philosopher Menedemus, the well-known asserter of a Providence, regarded with respect as sharing in his views. The same account is given by Aristæus. So the king left these works unlocked to all, in the Greek language. 
To this day, at the temple of Serapis, the libraries of Ptolemy are to be seen, with the identical Hebrew originals in them. The Jews, too, read them publicly. Under a tribute-liberty, they are in the habit of going to hear them every Sabbath. Whoever gives ear will find God in them; whoever takes pains to understand, will be compelled to believe.