Cain's offering was rejected by God because it was based on his works instead of faith.
The Bible reveals that Cain, the firstborn son of Adam and Eve, brought an offering from the fruit of the ground to the Lord. However, God had no regard for Cain's offering because it did not align with His revealed way of salvation, which required a blood sacrifice. In contrast, Abel's offering, which involved the firstlings of his flock and was offered with faith, was accepted by God. This teaches us that God's acceptance is based on faith and obedience, not merely on the efforts of our own hands. Cain's anger over God's rejection leads him to violence, illustrating the destructive nature of will-worship and self-righteousness that rejects God's prescribed way.
Commentary