What does Abel's blood teach us about human nature?

Abel's blood, as referenced in Hebrews 12:24, speaks of our inherent sin nature and the dire consequences of sin. When Abel was murdered by Cain, his blood cried out for justice, revealing the sinful heart of humanity—a heart inclined toward self-righteousness and rebellion against God's ways. This narrative illustrates that humans are born with a sinful disposition and are natural rebels, often seeking to earn favor with God through their good works rather than acknowledging their need for a blood sacrifice. The story serves as a sobering reminder of our sinful condition and the necessity of Christ's atoning blood, which is the only remedy for our guilt and separation from God.