6. Mark how close on the heels of sin God's question treads! How God spoke, we know not. Doubtless in some fashion suited to the needs of Cain. But He speaks to us as really as to him, and no sooner is the rush of passion over, and the bad deed done, than a revulsion comes. What we call conscience asks the question in stern tones, which make a man's flesh creep. Our sin is like touching the electric bells which people sometimes put on their windows to give notice of thieves. As soon as we step beyond the line of duty we set the alarm going, and it wakens the sleeping conscience. Some of us go so far as to have silenced the voice within; but, for the most part, it speaks immediately after we have gratified our inclinations wrongly. 7. Cain's defiant answer teaches us how a man hardens himself against God's voice. It also shows us how intensely selfish all sin is, and how weakly foolish its excuses are. It is sin which has rent men apart from men, and made them deny the very idea that they have duties to all men. The first sin was only against God; the second was against God and man. The first sin did not break, though it saddened, human love; the second kindled the flames of infernal hatred, and caused the first drops to flow of the torrents of blood which have soaked the earth. When men break away from God, they will soon murder one another. Cain was his brother's keeper. His question answered itself. If Abel was his brother, then he was bound to look after him. His self-condemning excuse is but a specimen of the shallow pleas by which the forgetfulness of duties we owe to all mankind, and all sins, are defended. 8. The stern sentence is next pronounced. First we have the grand figure of the innocent blood having a voice which pierces the heavens. That teaches in the most forcible way the truth that God knows the crimes done by 'man's inhumanity to man,' even when the meek sufferers are silent. According to the fine old legend of the cranes of Ibycus, a bird of the air will carry the matter. It speaks, too, of God's tender regard for His saints, whose blood is precious in His sight; and it teaches that He will surely requite. We cannot but think of the innocent blood shed on Calvary, of the Brother of us all, whose sacrifice was accepted of God. His blood, too, crieth from the ground, has a voice which speaks in the ear of God, but not to plead for vengeance, but pardon. 'Jesus' blood through earth and skies, Mercy, free, boundless mercy, cries.'