The LORD asks Cain why he is angry, and there appear to be two reasons. First, Cain is angry because God has rejected his efforts. This attitude is common today. Many people are angry at God because God rejects what the person has done. This is particularly evident in sexual ethics and among ethical people. Some people are angry that God would impinge upon their sexual desires. Other people are angry that God would not think they were good people, because by their own lights they are good people. In short, these people are angry at being called sinners, and most of us—Christian and non-Christian alike--have the same reaction when we feel accused of sin.
Cain is also angry that he has been rejected, but Abel has been accepted. Being found wanting as compared to another person is something we human beings find insufferable. In part this has to do with our insecurity in the universe: in a world where resources are scarce, where we play a zero-sum game – another person’s success could mean our failure. If someone gets a job, we can’t get it. If someone else is the center of attention, we are ignored. We’re often jealous for people’s affection, and if someone loves one person, we worry that he or she cares less for us. Perhaps Cain feels that he’s competing with Abel and losing.
But God assures Cain that there is enough love to go around: “If you do what is right, will you not be accepted?” (4:7). Cain’s problem is not that Abel has usurped his place with God, but that he has not acted acceptably. But God assures Cain there is no impediment to being accepted except changing his ways. The decision lies with Cain; it does not hinge on Abel.
As Christians we should particularly keep this in mind, since our jealousies are most likely to be aroused by our fellow Christians. We often live in closest proximity to our fellow Christians, and so it is easy to begin comparing our lives to theirs. We can compare our lives to theirs in standard terms (who has a better this, that, or the other thing), but we can also add a “spiritual” dimension to our jealousy, and to some extent begin to see other Christians’ blessings as proof that they have a better relationship with God than we do. But God’s statement to Cain suggests that God would not have any problem accepting all of his children—the only issue is whether they will conform their ways to God’s ways.
Unfortunately, Cain is unwilling to change his ways.