I address myself to give a condensed account of those things which are set forth in the sacred Scriptures from the beginning of the world and to tell of them, with distinction of dates and according to their importance, down to period within our own remembrance. Many who were anxious to become acquainted with divine things by means of a compendious treatise, have eagerly entreated me to undertake this work. I, seeking to carry out their wish, have not spared my labor, and have thus succeeded in comprising in two short books things which elsewhere filled many volumes.
At the same time, in studying brevity, I have omitted hardly any of the facts. Moreover, it seemed to me not out of place that, after I had run through the sacred history down to the crucifixion of Christ, and the doings of the Apostles, I should add an account of events which subsequently took place. I am, therefore, to tell of the destruction of Jerusalem, the persecutions of the Christian people, the times of peace which followed, and of all things again thrown into confusion by the intestine dangers of the churches.
But I will not shrink from confessing that, wherever reason required, I have made use of profane historians to fix dates and preserve the series of events unbroken, and have taken out of these what was wanting to a complete knowledge of the facts, that I might both instruct the ignorant and carry conviction to the learned. Nevertheless, as to those things which I have condensed from the sacred books, I do not wish so to present myself as an author to my readers, that they, neglecting the source from which my materials have been derived, should be satisfied with what I have written.
My aim is that one who is already familiar with the original should recognize here what he has read there; for all the mysteries of divine things cannot be brought out except from the fountain-head itself. I shall now enter upon my narrative.
Source: Sacred History (New Advent)