As if the crime of murder was not atrocious enough, Cain compounds his sin with a lie. When the Lord asks him about Abel’s whereabouts, Cain tells God that his brother’s location is unknown to him (Gen. 4:9). Furthermore, he addresses the Creator flippantly, claiming no responsibility for the well-being of his kin.
Moses’ original audience would have been especially disturbed by this account. First, an Israelite’s brother had the primary responsibility to rescue him if he was in trouble (Lev. 25:47–55). Cain does the opposite of what this obligation requires, revealing the flagrancy with which he breaks the covenant. Secondly, Leviticus says life is in the blood (17:11), and so the most defiling substance possible is the shed blood of an innocent person. Thus, Cain’s sin is particularly grave.
Again he refuses to repent when confronted with his sin. Cain is graciously given a chance to confess his iniquity, but he is too hardened to submit. John Calvin comments on how this passage warns us when we are convicted of sin. Though the Lord no longer confronts us audibly, “let those, therefore, whose consciences accuse them, beware lest, after the example of Cain, they confirm themselves in obstinacy.” We must not harden our hearts as Cain did.
Cain futilely imagines he can hide his trespass from God, for Abel’s blood cries out for justice (Gen. 4:10). The verb rendered “crying” in verse 10 is the same word used elsewhere to speak of the pleas of those who have met injustice (Ex. 22:22–23). When the Judge of all punishes Cain (Gen. 4:10–11), He demonstrates in practice what He promises by His word — that He always hears His faithful servants’ cries for vindication (Ex. 22:22–24; Ps. 135:14).
This promise is fulfilled in Christ who was vindicated by God in His resurrection (Rom. 8:11; 1 Tim. 3:16). His blood also cried for vengeance, and this plea was satisfied when sin and death were conquered. For the saints, the blood of Jesus speaks a better word than Abel’s (Heb. 12:24). Its just demand on believers is met at Calvary where, in bearing our penalty, the blood that destroys the wicked becomes for us a cleansing flood (9:11–14; 1 John 1:7).
Psalm 90:8 is a powerful reminder of our Lord’s all-seeing gaze. Though we might think we can sin in secret, God knows every evil deed we commit, even if no one else on the planet finds out. How have you transgressed the Lord in private? Do you honestly believe our Creator is not watching every thing you do? As you go about your daily business remember that God sees everything you do, and therefore your best attempt to hide your sin is useless.