17 To prove, to expound, to illustrate Catholic Doctrine by the legitimate and skilful interpretation of the Bible, is much; but there is a second part of the subject of equal importance and equal difficulty - the maintenance in the strongest possible way of its full authority. This cannot be done completely or satisfactorily except by means of the living and proper magisterium of the Church. The Church, "by reason of her wonderful propagation, her distinguished sanctity and inexhaustible fecundity in good, her Catholic unity, and her unshaken stability, is herself a great and perpetual motive of credibility, and an unassailable testimony to her own Divine mission."(45) But since the divine and infallible magisterium of the Church rests also on the authority of Holy Scripture, the first thing to be done is to vindicate the trustworthiness of the sacred records at least as human documents, from which can be clearly proved, as from primitive and authentic testimony, the Divinity and the mission of Christ our Lord, the institution of a hierarchical Church and the primacy of Peter and his successors. It is most desirable, therefore, that there should be numerous members of the clergy well prepared to enter upon a contest of this nature, and to repulse hostile assaults, chiefly trusting in that armour of God recommended by the Apostle,(46) but also not unaccustomed to modern methods of attack. This is beautifully alluded to by St. John Chrysostom, when describing the duties of priests: "We must use every endeavour that the 'Word of God may dwell in us abundantly'(47) and not merely for one kind of fight must we be prepared-for the contest is many-sided and the enemy is of every sort; and they do not all use the same weapons nor make their onset in the same way. Wherefore it is needful that the man who has to contend against all should be acquainted with the engines and the arts of all-that he should be at once archer and slinger, commandant and officer, general and private soldier, foot-soldier and horseman, skilled in sea-fight and in siege; for unless he knows every trick and turn of war, the devil is well able, if only a single door be left open, to get in his fierce bands and carry off the sheep."(48) The sophisms of the enemy and his manifold arts of attack we have already touched upon. Let us now say a word of advice on the means of defence. The first means is the study of the Oriental languages and of the art of criticism. These two acquirements are in these days held in high estimation, and therefore the clergy, by making themselves more or less fully acquainted with them as time and place may demand, will the better be able to discharge their office with becoming credit; for they must make themselves "all to all,"(49) always "ready to satisfy every one that asketh them a reason for the hope that is in them."(50) Hence it is most proper that Professors of Sacred Scripture and theologians should master those tongues in which the sacred Books were originally written; and it would be well that Church students also should cultivate them, more especially those who aspire to academic degrees. And endeavours should be made to establish in all academic institutions - as has already been laudably done in many - chairs of the other ancient languages, especially the Semitic, and of subjects connected therewith, for the benefit principally of those who are intended to profess sacred literature. These latter, with a similar object in view, should make themselves well and thoroughly acquainted with the art of true criticism. There has arisen, to the great detriment of religion, an inept method, dignified by the name of the "higher criticism," which pretends to judge of the origin, integrity and authority of each Book from internal indications alone. It is clear, on the other hand, that in historical questions, such as the origin and the handing down of writings, the witness of history is of primary importance, and that historical investigation should be made with the utmost care; and that in this matter internal evidence is seldom of great value, except as confirmation. To look upon it in any other light will be to open the door to many evil consequences. It will make the enemies of religion much more bold and confident in attacking and mangling the Sacred Books; and this vaunted "higher criticism" will resolve itself into the reflection of the bias and the prejudice of the critics. It will not throw on the Scripture the light which is sought, or prove of any advantage to doctrine; it will only give rise to disagreement and dissension, those sure notes of error, which the critics in question so plentifully exhibit in their own persons; and seeing that most of them are tainted with false philosophy and rationalism, it must lead to the elimination from the sacred writings of all prophecy and miracle, and of everything else that is outside the natural order.
Source: Providentissimus Deus (Vatican.va)