What does the Bible say about the sin of Cain?

The sin of Cain, as highlighted in the sermon, reveals a deep-seated hatred for the righteousness that is attributed to others. Cain's approach to worship was rooted in self-sufficiency and professional piety, leading him to believe that his own works were sufficient to earn God's favor. This self-righteousness ultimately resulted in his anger and violence against his brother Abel, who was approved by God through grace alone. Cain's actions serve as a warning against the dangers of self-reliance and pride in one's religious observances.