Let us watch our own hearts carefully in the matter of unbelief. The heart, and not the head, is the seat of its mysterious power. It is neither the lack of evidence, nor the difficulties of Christian doctrine, that make men unbelievers. It is lack of will to believe. They love sin. They are wedded to the world. In this state of mind they never lack specious reasons to confirm their will. The humble, childlike heart is the heart that believes.