Cain became "resentful and crestfallen" because Abel's offering was accepted by the Lord but Cain's offering was not (Gn 4:5-6). Then the Lord intervened and called Cain to repentance. He warned Cain: "Sin is a demon lurking at the door: his urge is toward you, yet you can be his master" (Gn 4:7). Cain refused to listen to the Lord and proceeded to commit the first murder (Gn 4:8).
When we sin, the Lord in His mercy intervenes. Unless we listen to Him and jump off the bandwagon of sin, it will take us to places where we don't want to be, to people we will regret being with, and to sins we never thought we'd do. The runaway train of sin will eventually lead us to death, damnation, and hell (see Rm 6:23).
Obviously, we should never get into the vehicle named "sin." But if we do sin, we must jump out of sin by accepting God's grace to repent, forgive, and confess our sins as soon as possible. Therefore:
- We should drop everything and lose no time in being reconciled with our brothers and sisters in Christ (Mt 5:24-25).
- "The sun must not go down on your wrath" (Eph 4:26).
- "See to it that no man falls away from the grace of God; that no bitter root springs up through which many may become defiled" (Heb 12:15).
"Sin is a demon lurking at the door" (Gn 4:7). Sin is a cancer which will spread and kill you unless you repent of all of it as quickly as possible. Repent and be sin's master (Gn 4:7).