John 9:39-41 Jesus said, “For judgment I came into this world, that those who do not see may see, and those who see may become blind.”40 Some of the Pharisees near him heard these things, and said to him, “Are we also blind?” 41 Jesus said to them, “If you were blind, you would have no guilt;  but now that you say, ‘We see,’ your guilt remains.
We see, lastly, in these verses, how dangerous it is to possess knowledge, if we do not make a good use of it. The rulers of the Jews were fully persuaded that they knew all religious truth. They were indignant at the very idea of being ignorant and devoid of spiritual eyesight. “Are we blind also?” they cried. And then came the mighty sentence, “If you were blind, you should have no sin–but now you say, ‘We see’; therefore your sin remains.”
Knowledge undoubtedly is a very great blessing. The man who cannot read, and is utterly ignorant of Scripture, is in a pitiable condition. He is at the mercy of any false teacher who comes across him, and may be taught to take up any absurd creed, or to follow any vicious practice. Almost any education is better than no education at all.
But when knowledge only sticks in a man’s head, and has no influence over his heart and life, it becomes a most perilous possession. And when, in addition to this, its possessor is self-conceited and self-satisfied, and imagines he knows everything, the result is one of the worst states of soul into which man can fall. There is far more hope about him who says, “I am a poor blind sinner and want God to teach me,” than about him who is ever saying, “I know it, I know it, I am not ignorant,” and yet cleaves to his sins. The sin of that man “remains.”
Let us use diligently whatever religious knowledge we possess, and ask continually that God would give us more. Let us never forget that the devil himself is a creature of vast head-knowledge, and yet none the better for it, because it is not rightly used. Let our constant prayer be that which David so often sent up in the hundred and nineteenth Psalm. “Lord, teach me your statutes give me understanding–unite my heart to fear Your name.”