Translated from the Greek
8 Having spoken thus briefly on the subject of the divine inspiration of the holy Scriptures, it is necessary to proceed to the (consideration of the) manner in which they are to be read and understood, seeing numerous errors have been committed in consequence of the method in which the holy documents ought to be examined; not having been discovered by the multitude. For both the hardened in heart, and the ignorant persons belonging to the circumcision, have not believed on our Saviour, thinking that they are following the language of the prophecies respecting Him, and not perceiving in a manner palpable to their senses that He had proclaimed liberty to the captives, nor that He had built up what they truly consider the city of God, nor cut off “the chariots of Ephraim, and the horse from Jerusalem,” nor eaten butter and honey, and, before knowing or preferring the evil, had selected the good. And thinking, moreover, that it was prophesied that the wolf— the four-footed animal— was to feed with the lamb, and the leopard to lie down with the kid, and the calf and bull and lion to feed together, being led by a little child, and that the ox and bear were to pasture together, their young ones growing up together, and that the lion was to eat straw like the ox: seeing none of these things visibly accomplished during the advent of Him who is believed by us to be Christ, they did not accept our Lord Jesus; but, as having called Himself Christ improperly, they crucified Him. And those belonging to heretical sects reading this (statement), “A fire has been kindled in Mine anger;” and this, “I am a jealous God, visiting the iniquities of the fathers upon the children unto the third and fourth generation;” and this, “I repent of having anointed Saul to be king;” and this, “I am a God that makes peace, and creates evil;” and, among others, this, “There is not wickedness in the city which the Lord has not done;” and again this, “Evils came down from the Lord upon the gates of Jerusalem;” and, “An evil spirit from the Lord plagued Saul;” and countless other passages like these— they have not ventured to disbelieve these as the Scriptures of God; but believing them to be the (words) of the Demiurge, whom the Jews worship, they thought that as the Demiurge was an imperfect and unbenevolent God, the Saviour had come to announce a more perfect Deity, who, they say, is not the Demiurge, being of different opinions regarding Him; and having once departed from the Demiurge, who is the only uncreated God, they have given themselves up to fictions, inventing to themselves hypotheses, according to which they imagine that there are some things which are visible, and certain other things which are not visible, all which are the fancies of their own minds. And yet, indeed, the more simple among those who profess to belong to the Church have supposed that there is no deity greater than the Demiurge, being right in so thinking, while they imagine regarding Him such things as would not be believed of the most savage and unjust of mankind.
9. Now the cause, in all the points previously enumerated, of the false opinions, and of the impious statements or ignorant assertions about God, appears to be nothing else than the not understanding the Scripture according to its spiritual meaning, but the interpretation of it agreeably to the mere letter. And therefore, to those who believe that the sacred books are not the compositions of men, but that they were composed by inspiration of the Holy Spirit, agreeably to the will of the Father of all things through Jesus Christ, and that they have come down to us, we must point out the ways (of interpreting them) which appear (correct) to us, who cling to the standard of the heavenly Church of Jesus Christ according to the succession of the apostles. Now, that there are certain mystical economies made known by the holy Scriptures, all— even the most simple of those who adhere to the word— have believed; but what these are, candid and modest individuals confess that they know not. If, then, one were to be perplexed about the intercourse of Lot with his daughters, and about the two wives of Abraham, and the two sisters married to Jacob, and the two handmaids who bore him children, they can return no other answer than this, that these are mysteries not understood by us. Nay, also, when the (description of the) fitting out of the tabernacle is read, believing that what is written is a type, they seek to adapt what they can to each particular related about the tabernacle,— not being wrong so far as regards their belief that the tabernacle is a type of something, but erring sometimes in adapting the description of that of which the tabernacle is a type, to some special thing in a manner worthy of Scripture. And all the history that is considered to tell of marriages, or the begetting of children, or of wars, or any histories whatever that are in circulation among the multitude, they declare to be types; but of what in each individual instance, partly owing to their habits not being thoroughly exercised— partly, too, owing to their precipitation— sometimes, even when an individual does happen to be well trained and clear-sighted, owing to the excessive difficulty of discovering things on the part of men—the nature of each particular regarding these (types) is not clearly ascertained.
10. And what need is there to speak of the prophecies, which we all know to be filled with enigmas and dark sayings? And if we come to the Gospels, the exact understanding of these also, as being the mind of Christ, requires the grace that was given to him who said, “But we have the mind of Christ, that we might know the things freely given to us by God. Which things also we speak, not in the words which man's wisdom teaches, but which the Spirit teaches.” And who, on reading the revelations made to John, would not be amazed at the unspeakable mysteries therein concealed, and which are evident (even) to him who does not comprehend what is written? And to what person, skilful in investigating words, would the Epistles of the Apostles seem to be clear and easy of understanding, since even in them there are countless numbers of most profound ideas, which, (issuing forth) as by an aperture, admit of no rapid comprehension? And therefore, since these things are so, and since innumerable individuals fall into mistakes, it is not safe in reading (the Scriptures) to declare that one easily understands what needs the key of knowledge, which the Saviour declares is with the lawyers. And let those answer who will not allow that the truth was with these before the advent of Christ, how the key of knowledge is said by our Lord Jesus Christ to be with those who, as they allege, had not the books which contain the secrets of knowledge, and perfect mysteries. For His words run thus: “Woe unto you, you lawyers! For you have taken away the key of knowledge: you have not entered in yourselves, and them that were entering in you hindered.”
Source: De Principiis (New Advent)