This sermon uses the biblical story of Cain and Abel from Genesis 4 to highlight the principle that our actions have consequences. It contrasts Abel's faithful offering with Cain's rejection, which led to anger, bitterness, and ultimately murder. The message emphasizes that while sin leads to negative outcomes, God's mercy is available through Jesus Christ, offering forgiveness and salvation from the ultimate consequence of sin. The sermon concludes with a call for both non-believers and Christians to repent, urging them to confess their sins and accept God's grace.