3 Among the reasons for which the Holy Scripture is so worthy of commendation - in addition to its own excellence and to the homage which we owe to God's Word - the chief of all is, the innumerable benefits of which it is the source; according to the infallible testimony of the Holy Ghost Himself, who says: "All Scripture, inspired of God, is profitable to teach, to reprove, to correct, to instruct in justice, that the man of God may be perfect, furnished to every good work."(6) That such was the purpose of God in giving the Scripture of men is shown by the example of Christ our Lord and of His Apostles. For He Himself Who "obtained authority by miracles, merited belief by authority, and by belief drew to Himself the multitude"(7) was accustomed in the exercise of His Divine Mission, to appeal to the Scriptures. He uses them at times to prove that He is sent by God, and is God Himself. From them He cites instructions for His disciples and confirmation of His doctrine. He vindicates them from the calumnies of objectors; he quotes them against Sadducees and Pharisees, and retorts from them upon Satan himself when he dares to tempt Him. At the close of His life His utterances are from Holy Scripture, and it is the Scripture that He expounds to His disciples after His resurrection, until He ascends to the glory of His Father. Faithful to His precepts, the Apostles, although He Himself granted "signs and wonders to be done by their hands"(8) nevertheless used with the greatest effect the sacred writings, in order to persuade the nations everywhere of the wisdom of Christianity, to conquer the obstinacy of the Jews, and to suppress the outbreak of heresy. This is plainly seen in their discourses, especially in those of St. Peter: these were often little less than a series of citations from the Old Testament supporting in the strongest manner the new dispensation. We find the same thing in the Gospels of St. Matthew and St. John and in the Catholic Epistles; and most remarkably of all in the words of him who "boasts that he learned the law at the feet of Gamaliel, in order that, being armed with spiritual weapons, he might afterwards say with confidence, `The arms of our warfare are not carnal but mighty unto God.' "(9) Let all, therefore, especially the novices of the ecclesiastical army, understand how deeply the sacred Books should be esteemed, and with what eagerness and reverence they should approach this great arsenal of heavenly arms. For those whose duty it is to handle Catholic doctrine before the learned or the unlearned will nowhere find more ample matter or more abundant exhortation, whether on the subject of God, the supreme Good and the all-perfect Being, or of the works which display His Glory and His love. Nowhere is there anything more full or more express on the subject of the Saviour of the world than is to be found in the whole range of the Bible. As St. Jerome says, "To be ignorant of the Scripture is not to know Christ."(10) In its pages His Image stands out, living and breathing; diffusing everywhere around consolation in trouble, encouragement to virtue and attraction to the love of God. And as to the Church, her institutions, her nature, her office, and her gifts, we find in Holy Scripture so many references and so many ready and convincing arguments, that as St. Jerome again most truly says: "A man who is well grounded in the testimonies of the Scripture is the bulwark of the Church."(11)And if we come to morality and discipline, an apostolic man finds in the sacred writings abundant and excellent assistance; most holy precepts, gentle and strong exhortation, splendid examples of every virtue, and finally the promise of eternal reward and the threat of eternal punishment, uttered in terms of solemn import, in God's name and in God's own words.
Source: Providentissimus Deus (Vatican.va)