What does the Bible say about the difference between Cain and Abel?

In Genesis 4, we see the stark contrast between Cain and Abel, both raised in the same household and exposed to the same teachings about God. The only differentiating factor between them was the grace that God bestowed upon Abel. Ephesians 2 reminds us that salvation is by grace through faith, not a result of our efforts. Abel found favor in God's eyes because he brought the appropriate sacrifice—a lamb, signifying the blood atonement required for worship—while Cain offered fruits from the cursed ground, representing works of his own pride. This illustrates the core Reformed belief that it is God's sovereign choice to grant grace to whom He wills, making the distinction clear.