The Danger of Unsanctified Head-Knowledge by J.C. Ryle
Let us pray that we may be delivered from a cold, speculative, unsanctified head-knowledge of Christianity.
It is a rock on which thousands make shipwreck to all eternity. No heart becomes so hard as that on which the light shines, but finds no admission. To be an ignorant heathen, and bow down to idols and stones, is bad enough. But to be called a Christian, and know the theory of the Gospel, and yet cleave to sin and the world with the heart, is to be a candidate for the worst and lowest place in hell. It is to be as like as possible to the devil.