After Adam and Eve were expelled from the Garden of Eden, they settled in the ‘outside’ world. They had their first son, Cain, then Abel.
Both sons brought offerings to the Lord. Cain brought some of the fruits of the soil. Abel brought fat portions from some of the firstborn of his flock. God accepted Abel’s offer, but did not have much regard for Cain’s (Genesis 4:1-8). Why? God explained a principle to Adam and Eve in the Garden of Eden after they disobeyed God,
‘The Lord God made garments of skin for Adam and his wife and clothed them.’ Genesis 3:21
God warned them earlier that they would die if they eat from the tree of the knowledge of good and evil. They ate, they disobeyed, they sinned against God. God demonstrated His ‘Exchange Program’ in real life – He killed innocent animals and clothed Adam and Eve with the skins. Since they were the first sinners, deceived by the devil, God forgave them in that way. The principle is,
‘…without the shedding of blood there is no forgiveness.’ Hebrews 9:22b
Adam and Eve must have understood it, and taught it to their children. Abel offered to God in the right way. Cain, in contradiction to God’s design for forgiveness, offered in the wrong way. When God disapproved,
‘…Cain was very angry and his face was downcast.’ Genesis 4:5b
God obviously noticed it, and addressed Cain,
‘If you do what is right, will you not be accepted?’ Genesis 4:5
Cain showed no remorse. He lived his life as he wanted. He is never mentioned as a righteous man in the Bible.
Abel had a different outcome, even though his life was cut short,
‘By faith Abel offered God a better sacrifice than Cain did. By faith he was commended as a righteous man, when God spoke well of his offering.’ Hebrews 11:4
Cain and Abel demonstrate how important it is to understand God’s Exchange Program. It points to the final Sacrifice, Jesus. Through faith in Him we can also be commended as righteous and have the hope of eternal life with God.