One thing that took me awhile to learn was reading for profitability, not reading for the sake of reading. There are far too many good, worthwhile books that cause your soul to stir and affections to swell for God than to waste your time (and eyes) reading bad books that produce little fruit. Here is some advice from Thomas Brooks in his previously mentioned The Mute Christian Under the Smarting Rod for reading for profit
For, as many fish and catch nothing, Luke 5:5, so many read good books and get nothing, because they read them over cursorily, slightly, superficially; but he who would read to profit, must then,
First, Read and look up for a blessing—’Paul may plant, and Apollos may water,’ but all will be to no purpose, except ‘the Lord gives the increase,’ 1 Cor. 3:6, 7. God must do the deed, when all is done, or else all that is done will do you no good. If you would have this work successful and effectual, you must look off from man—and look up to God, who alone can make it a blessing to you. As without a blessing from heaven, your clothes cannot warm you, nor your food nourish you, nor medicine cure you, nor friends comfort you, Micah 6:14; so without a blessing from heaven, without the precious breathings and influences of the Spirit, what here is written will do you no good, it will not turn to your account in the day of Christ; therefore cast an eye heavenwards, Haggai 1:6.
It is Seneca’s observation, that the husbandmen in Egypt never look up to heaven for rain in the time of drought—but look after the overflowing of the banks of Nile, as the only cause of their plenty. Ah, how many are there in these days, who, when they go to read a book, never look up, never look after the rain of God’s blessing—but only look to the river Nile; they only look to the wit, the learning, the arts, the parts, the eloquence, etc., of the author, they never look so high as heaven; and hence it comes to pass, that though these read much, yet they profit little.
Secondly, He who would read to profit must read and meditate. Meditation is the food of your souls, it is the very stomach and natural heat whereby spiritual truths are digested. A man shall as soon live without his heart, as he shall be able to get good by what he reads, without meditation. Prayer, says Bernard, without meditation, is dry and formal; and reading without meditation is useless and unprofitable. He who would be a wise, a prudent, and an able experienced statesman, must not hastily ramble and run over many cities, countries, customs, laws, and manners of people, without serious musing and pondering upon such things as may make him an expert statesman; so he who would get good by reading, that would complete his knowledge, and perfect his experience in spiritual things, must not slightly and hastily ramble and run over this book or that—but ponder upon what he reads, as Mary pondered the saying of the angel in her heart.
Lord! says Augustine, the more I meditate on you, the sweeter you are to me; so the more you shall meditate on the following matter, the sweeter it will be to you. They usually thrive best who meditate most. Meditation is a soul-fattening duty; it is a grace-strengthening duty, it is a duty-crowning duty. Meditation is the nurse of prayer. Jerome calls it his paradise; Basil calls it the treasury where all the graces are locked up; Theophylact calls it the very gate and portal by which we enter into glory; and Aristotle, though a heathen, places felicity in the contemplation of the mind. You may read much and hear much—yet without meditation you will never be excellent, you still never be eminent Christians.
Thirdly, Read, and test what you read; take nothing upon trust—but all upon trial, as those ‘noble Bereans’ did, Acts 17:to, 11. You will try and count and weigh gold, though it be handed to you by your fathers; and so should you all those heavenly truths that are handed to you by your spiritual fathers. I hope upon trial you will find nothing—but what will hold weight in the balance of the sanctuary; and though all be not gold that glitters, yet I judge that you will find nothing here to blister, that will not be found upon trial to be true gold.
Fourthly, Read and do, read and practice what you read, or else all your reading will do you no good. He who has a good book in his hand—but not a lesson of it in his heart or life, is like that donkey that carries burdens, and feeds upon thistles. In divine account, a man knows no more than be does. Profession without practice will but make a man twice told a child of darkness. To speak well is to sound like a cymbal—but to do well is to act like an angel [Isidore]. He who practices what he reads and understands, God will help him to understand what he understands not. There is no fear of knowing too much, though there is much fear in practicing too little; the most doing man, shall be the most knowing man; the mightiest man in practice, will in the end prove the mightiest man in Scripture, John 7:16, 17, Psalm 119:98-100. Theory is the guide of practice, and practice is the life of theory.
Salvian relates how the heathen did reproach some Christians, who by their lewd lives made the gospel of Christ to be a reproach. ‘Where,’ said they, ‘is that good law which they believe? Where are those rules of godliness which they learn? They read the holy gospel, and yet are unclean; they read the apostles’ writings, and yet live in drunkenness; they follow Christ, and yet disobey Christ; they profess a holy law, and yet lead impure lives.’ Ah! how may many preachers take up sad complaints against many readers in these days! They read our works, and yet in their lives they deny our works; they praise our works, and yet in their lives they reproach our works; they cry up our labors in their discourses, and yet they cry them down in their practices—yet I hope better things of you into whose hands this treatise shall fall. The Samaritan woman did not fill her pitcher with water, that she might talk of it—but that she might use it, John 4:7; and Rachel did not desire the mandrakes to hold in her hand—but that she might thereby be the more apt to bring forth, Gen. xxx. 15. The application is easy. But,
Fifthly, Read and apply. Reading is but the drawing of the bow, application is the hitting of the bulls-eye. The choicest truths will no further profit you than they are applied by you. It would be as good not to read, as not to apply what you read. No man attains to health by reading books on health—but by the practical application of their remedies. All the reading in the world will never make for the health of your souls—except you apply what you read. The true reason why many read so much and profit so little—is because they do not apply and bring home what they read to their own souls. But,
Sixthly, and lastly, Read and pray. He who makes not conscience of praying over what he reads, will find little sweetness or profit in his reading. No man makes such earnings of his reading, as he who prays over what he reads. Luther professes that he profited more in the knowledge of the Scriptures by prayer, in a short space, than by study in a longer. As John by weeping got the sealed book open, so certainly men would gain much more than they do by reading good men’s works, if they would but pray more over what they read! Ah, Christians! pray before you read, and pray after you read, that all may be blessed and sanctified to you; when you have done reading, usually close up thus—So let me live, so let me die, that I may live eternally.
And when you are in the mount for yourselves, bear him upon your hearts, who is willing to ‘spend and be spend’ for your sakes, for your souls, 2 Cor. 12:15. Oh! pray for me, that I may more and more be under the rich influences and glorious pourings out of the Spirit; that I may ‘be an able minister of the New Testament—not of the letter—but of the Spirit,’ 2 Cor. 3:6; that I may always find an everlasting spring and an overflowing fountain within me, which may always make me faithful, constant, and abundant in the work of the Lord; and that I may live daily under those inward teachings of the Spirit, which may enable me to speak from the heart to the heart, from the conscience to the conscience, and from experience to experience; that I may be a ‘burning and a shining light,’ that everlasting arms may be still under me; that while I live, I may be serviceable to his glory and his people’s good; that no discouragements may discourage one in my work; and that when my work is done, I may give up my account with joy and not with grief. I shall follow these poor labors with my weak prayers, that they may contribute much to your internal and eternal welfare.”
Image Credit: http://acheronic.deviantart.com/art/Tolle-Lege-70881656