It is no mere imagination that, in a moment, the mind may be so quickened as to embrace the actions of a long period; and that with equal suddenness the moral aspect of them may be completely changed. There are moments when the powers of the mind as well as those of the body are so stimulated as to become capable of exertions undreamt of before. The dumb prince, in ancient history, who all his life had never spoken a word, but found the power of speech when he saw a sword raised to cut down his father, showed how danger could stimulate the organs of the body. The sudden change in David's feeling now, like the sudden change in Saul's on the way to Damascus, showed what electric rapidity may be communicated to the operations of the soul. It showed too what unseen and irresistible agencies of conviction and condemnation the great Judge can bring into play when it is His will to do so. As the steam hammer may be so adjusted as either to break a nutshell without injuring the kernel, or crush a block of quartz to powder, so the Spirit of God can range, in His effects on the conscience, between the mildest feeling of uneasiness and the bitterest agony of remorse. "When He is come," said our blessed Lord, "He shall reprove the world of sin." How helpless men are under His operation! How utterly was David prostrated! How were the multitudes brought down on the day of Pentecost! Is there any petition we more need to press than that the Spirit be poured out to convince of sin, whether as it regards ourselves or the world? Is it not true that the great want of the Church the want of is a sense of sin, so that confession and humiliation are become rare, and our very theology is emasculated, because, where there is little sense of sin, there can be little appreciation of redemption? And is not a sense of sin that which would bring a careless world to itself, and make it deal earnestly with God's gracious offers? How striking is the effect ascribed by the prophet Zechariah to that pouring of the spirit of grace and supplication upon the house of David and the inhabitants of Jerusalem, when "they shall look on Him whom they have pierced, and shall mourn for Him as one mourneth for an only son, and shall be in bitterness for Him as one that is in bitterness for his firstborn." Would that our whole hearts went out in those invocations of the Spirit which we often sing, but alas! so very tamely-- "Come, Holy Spirit, come, Let Thy bright beams arise; Dispel the darkness from our minds, And open all our eyes. "Convince us of our sin, Lead us to Jesus' blood, And kindle in our breast the flame Of never-dying love."