Ante-Nicene Fathers, Vol III:
Tertullian: Part I: Chapter V.

Chapter V.

These testimonies of the soul are simple as true, commonplace as simple, universal as commonplace, natural as universal, divine as natural.  I don’t think they can appear frivolous or feeble to any one, if he reflect on the majesty of nature, from which the soul derives its authority. 1487 If you acknowledge the authority of the mistress, you will own it also in the disciple.  Well, nature is the mistress here, and her disciple is the soul. But everything the one has taught or the other learned, has come from God—the Teacher of the teacher. And what the soul may know from the teachings of its chief instructor, thou canst judge from that which is within thee. Think of that which enables thee to think; reflect on that which in forebodings is the prophet, the augur in omens, the foreseer of coming events. Is it a wonderful thing, if, being the gift of God to man, it knows how to divine? Is it anything very strange, if it knows the God by whom it was bestowed? Even fallen as it is, the victim of the great adversary’s machinations, it does not forget its Creator, His goodness and law, and the final end both of itself and of its foe. Is it singular then, if, divine in its origin, its revelations agree with the knowledge God has given to His own people? But he who does not regard those outbursts of the soul as the teaching of a congenital nature and the secret deposit of an inborn knowledge, will say that the habit and, so to say, the vice of speaking in this way has been acquired and confirmed from the opinions of published books widely spread among men.  Unquestionably the soul existed before letters, and speech before books, and ideas before the writing of them, and man himself before the poet and philosopher. 1488 Is it then to be believed, that before literature and its publication no utterances of the sort we have pointed out came from the lips of men? Did nobody speak of God and His goodness, nobody of death, nobody of the dead? Speech went a-begging, I suppose; nay, (the subjects being still awanting, without which it cannot even exist at this day, when it is so much more copious, and rich, and wise), it could not exist at all if the things which are now so easily suggested, that cling to us so constantly, that are so very near to us, that are somehow born on our very lips, had no existence in ancient times, before letters had any existence in the world—before there was a Mercury, I think, at all. And whence was it, I pray, that letters themselves came to know, and to disseminate for the use of speech, what no mind had ever conceived, or tongue put forth, or ear taken in? But, clearly, since the Scriptures of God, whether belonging to Christians or to Jews, into whose olive tree we have been grafted—are much more ancient than any secular literature, (or, let us only say, are of a somewhat earlier date, as we have shown in its proper place when proving their trustworthiness); if the soul have taken these utterances from writings at all, we must believe it has taken them from ours, and not from yours, its instruction coming more naturally from the earlier than the later works. Which latter indeed waited for their own instruction from the former, and though we grant that light has come from you, still it has flowed from the first fountainhead originally; and we claim as p. 179 entirely ours, all you may have taken from us and handed down. Since it is thus, it matters little whether the soul’s knowledge was put into it by God or by His book. Why, then, O man, wilt thou maintain a view so groundless, as that those testimonies of the soul have gone forth from the mere human speculations of your literature, and got hardening of common use?

Footnotes

[This appeal to the universal conscience and consciousness of mankind is unanswerable, and assures us that counter-theories will never prevail.  See Bossuet, De la Connoisance de Dieu et de Soi-même. Œuvres, Tom. V. pp. 86 et. seqq. Ed. Paris, 1846.]

[Compare the heathen ideas in Plato: e.g. the story Socrates tells in the Gorgias, (near the close) about death and Judgment.]