Here’re some quotes. 
‘The lamb of thy body is the eye. If the eye be sound, thy whole body will be full of light. But if it be evil, thy body will be full of darkness. Take care, therefore, that the light that is in thee is not darkness. If, then, thy whole body is full of light, having no part in darkness, it will all be illumined, as when a bright lamp illumines thee.’
The Lord (Luke 11:33-36)
‘Idleness is the enemy of the soul; and therefore the brethren ought to be employed in manual labor at certain times, at others, in devout reading.’
St. Benedict
‘Let us love God, but let it be with the strength of our arms and the sweat of our brow.’
‘Read good and useful books, and abstain from reading those that only gratify curiosity.’
St. Vincent de Paul
‘You will not see anyone who is really striving after his advancement who is not given to spiritual reading. And as to him who neglects it, the fact will soon be observed by his progress.’
St. Athanasius
‘As for joy, as little as one can have of it in this life, experience shows that it is not the idle who possess it, but those who are zealous in the service of God.’
‘Idleness begets a discontented life. It develops self-love, which is the cause of all our misery, and renders us unworthy to receive the favors of divine love.’
‘Idleness is hell’s fishhook for catching souls.’
St. Ignatius of Loyola
'The reading of spiritual works is as profitable as the reading of bad books is noxious. As the former has led to the conversion of many sinners, so the latter is every day the ruin of many young persons. The first author of pious books is the Spirit of God; but the author of pernicious writings is the devil, who often artfully conceals from certain persons the poison that such works contain, and makes these persons believe that the reading of such books is necessary in order to speak well, and to acquire a knowledge of the world for their own direction, or at least in order to pass the time agreeably. But I say that, especially for nuns, nothing is more pernicious than the reading of bad books. And by bad books I mean not only those that are condemned by the Holy See, either because they contain heresy, or treat of subjects opposed to chastity, but also all books that treat of worldly love. What fervor can a religious have if she reads romances, comedies, or profane poetry? What recollection can she have in meditation or at Communion? Can she be called the spouse of Jesus Christ? Should she not rather be called the spouse of a sinful world? Even young women in the world that are in the habit of reading such books are generally not virtuous seculars.
But some one may say, What harm is there in reading romances and profane poetry when they contain nothing immodest? Do you ask what harm? Behold the harm: the reading of such works kindles the concupiscence of the senses, and awakens the passions; these easily gain the consent of the will, or at least render it so weak that when the occasion of any dangerous affection occurs the devil finds the soul already prepared to allow itself to be conquered. A wise author has said that by the reading of such pernicious books heresy has made, and makes every day, great progress; because such reading has given and gives increased strength to libertinism. The poison of these books enters gradually into the soul; it first makes itself master of the understanding, then infects the will, and in the end kills the soul. The devil finds no means more efficacious and secure of sending a young person to perdition than the reading of such poisoned works.’
Remember also that for you certain useless books, though not bad, will be pernicious; because they will make you lose the time that you can employ in occupations profitable to the soul. In a letter to his disciple Eustochium, St. Jerome stated for her instruction that in his solitude at Bethlehem he was attached to the works of Cicero, and frequently read them, and that he felt a certain disgust for pious books because their style was not polished. He was seized with a serious malady, in which he saw himself at the tribunal of Jesus Christ. The Lord said to him: “Tell me; what are you?” “I am,” replied the saint, “a Christian.” “No,” rejoined the Judge, “you are a Ciceronian, not a Christian.” He then commanded him to be instantly scourged. The saint promised to correct his fault, and having returned from the vision he found his shoulders livid and covered with wounds in consequence of the chastisement that he had received. Thenceforward he gave up the works of Cicero, and devoted himself to the reading of books of piety. It is true that in the works like those of Cicero we sometimes find useful sentiments; but the same St. Jerome wisely said in a letter to another disciple: “What need have you of seeking for a little gold in the midst of so much mire,” when you can read pious books in which you may find all gold without any mire?’
St. Alphonsus Maria de Liguori
‘For the rest, brethren, whatsoever is true, whatsoever is modest, whatsoever is just, whatsoever is pure, whatsoever is lovely, whatsoever is gracious, if there is any virtue, if there is any discipline worthy of praise, think on these.’
St. Paul (Philippians 4:8)
