II. Cain's plea: he pleads not guilty, and adds rebellion to his sin. For, 1. He endeavours to cover a deliberate murder with a deliberate lie: I know not. He knew well enough what had become of Abel, and yet had the impudence to deny it. Thus, in Cain, the devil was both a murderer and a liar from the beginning. See how sinners' minds are blinded, and their hearts hardened by the deceitfulness of sin: those are strangely blind that think it possible to conceal their sins from a God that sees all, and those are strangely hard that think it desirable to conceal them from a God who pardons those only that confess. 2. He impudently charges his Judge with folly and injustice, in putting this question to him: Am I my brother's keeper? He should have humbled himself, and have said, Am not I my brother's murderer? But he flies in the face of God himself, as if he had asked him an impertinent question, to which he was no way obliged to give an answer: "Am I my brother's keeper? Surely he is old enough to take care of himself, nor did I ever take any charge of him." Some think he reflects on God and his providence, as if he had said, "Art not thou his keeper? If he be missing, on thee be the blame, and not on me, who never undertook to keep him." Note, A charitable concern for our brethren, as their keepers, is a great duty, which is strictly required of us, but is generally neglected by us. Those who are unconcerned in the affairs of their brethren, and take no care, when they have opportunity, to prevent their hurt in their bodies, goods, or good name, especially in their souls, do, in effect, speak Cain's language. See Lev. xix. 17; Phil. ii. 4.
III. The conviction of Cain, v. 10. God gave no direct answer to his question, but rejected his plea as false and frivolous: "What hast thou done? Thou makest a light matter of it; but hast thou considered what an evil thing it is, how deep the stain, how heavy the burden, of this guilt is? Thou thinkest to conceal it, but it is to no purpose, the evidence against thee is clear and incontestable: The voice of thy brother's blood cries." He speaks as if the blood itself were both witness and prosecutor, because God's own knowledge testified against him and God's own justice demanded satisfaction. Observe here, 1. Murder is a crying sin, none more so. Blood calls for blood, the blood of the murdered for the blood of the murderer; it cries in the dying words of Zechariah (2 Chron. xxiv. 22), The Lord look upon it and require it; or in those of the souls under the altar (Rev. vi. 10), How long, Lord, holy, and true? The patient sufferers cried for pardon (Father, forgive them), but their blood cries for vengeance. Though they hold their peace, their blood has a loud and constant cry, to which the ear of the righteous God is always open. 2. The blood is said to cry from the ground, the earth, which is said to open her mouth to receive his brother's blood from his hand, v. 11. The earth did, as it were, blush to see her own face stained with such blood, and therefore opened her mouth to hide that which she could not hinder. When the heaven revealed Cain's iniquity, the earth also rose up against him (Job xx. 27), and groaned on being thus made subject to vanity, Rom. viii. 20, 22. Cain, it is likely, buried the blood and the body, to conceal his crime; but "murder will out." He did not bury them so deep but the cry of them reached heaven. 3. In the original the word is plural, thy brother's bloods, not only his blood, but the blood of all those that might have descended from him; or the blood of all the seed of the woman, who should, in like manner, seal the truth with their blood. Christ puts all on one score (Matt. xxiii. 35); or because account was kept of every drop of blood shed. How well is it for us that the blood of Christ speaks better things than that of Abel! Heb. xii. 24. Abel's blood cried for vengeance, Christ's blood cries for pardon.
http://www.ccel.org/ccel/henry/mhc1.Gen.v.html
