The real difficulty of Scripture consists in its thoughts being so infinitely above our natural mind. We must give up self in order to understand the Bible. We must have a heart and an eye for Christ, or Scripture becomes an unintelligible thing for our souls; whereas, when the eye is single, the whole body is full of light.
Hence we see every day a learned man completely at fault, though he may be a Christian—stopping short at the Epistles of John or at the Revelation as being too deep for him to enter into While, on the other hand, you may find a simple man, who, if he cannot altogether understand these Scriptures or explain every portion of them correctly, can at any rate enjoy them; they convey intelligible thoughts to his soul, and comfort and guidance, and profit too. Even if it be about coming events, or Babylon and the beast, he finds there great principles of God which, even though they may be found in what is reputed to be the obscurest of all the books of Scripture, yet have a practical bearing for his soul. The reason is, Christ is before him, and Christ is the wisdom of God in every sense. Nor is it because a man is learned that he is capable of entering into the thoughts of God. Whether ignorant or learned, there is but one way―the eye to see what concerns Christ.
Where Christ is firmly fixed before the soul, I believe that He becomes the light of spiritual intelligence as He is the light of salvation. It is the Spirit of God who is the power for us to apprehend it; but He never gives that light except through Christ. Otherwise man has an object before him that is not Christ, and therefore cannot understand Scripture which reveals Christ. He is endeavoring to force the Scriptures to bear upon his own objects, whatever they may be, and thus Scripture is perverted. Such is the real key to all the mistakes concerning scripture. Man takes his own thoughts to the Word of god, and builds up a system which has no divine foundation.
Extract From “Notes on Daniel” by William Kelly, p. 90, 91