Click to read Genesis 4
The farmer and the shepherd
This chapter starts of with the announcement of the birth of 2 sons, Cain and Abel. We don't know how much time was in between them, only that Abel was born later. Another thing we know is that the former was a farmer and the latter a shepherd.
Offering
We don't know when people started offering to God and we don't know why. We do know that God could be pleased with an offer, He looked at Abel's offering with favour. Abel offered fat portions of some of the firstborn in his flock and Cain some of the fruits of the field. The Bible doesn't disclose why God favoured the former offer but not the latter. It is likely that the reason for this was that Abel offered the best of the best while Cain just gave something. God also reprimands Cain when he is angry that God didn't look with favour at his offering. He warns Cain to do what is right, so Cain must have somehow disobeyed God is his offering or maybe it was his temper, in order to keep the sin at bay. He tells Cain that he must learn to control it.
The first murder
Cain takes Abel into the field where he murders him. This isn't only a murder, this is a premeditated murder. Cain takes Abel somewhere nobody is around so he can do what he wants to do. But God knows. God gives Cain a chance to come clean, just like with Adam and Eve, before he starts to reprimand Cain. I find this a very beautiful sign and I wonder what had happened if in one or both cases they had come clean before God started reprimanding them.
The punishment
Cain, who as we read before was a farmer, gets exiled. He is condemned to the life of a wanderer, and won't be able to do his profession anymore. Cain is condemned to the life of a gatherer since it is only after the flood that God allows humans to eat meat. This punishment seemed unbearable for Cain and one of the things he mentioned what that he would be hidden from the presence of God. Cain still wanted to be close to God.
Whoever finds me will kill me
Cain is scared that at some point in the future someone will find him and kill him because he killed his brother. This however, doesn't mean that is was an immediate threat. In those days people lived for hundreds of years, and it is not unthinkable that in a hundred years that someone might go on a "crusade" against him. God placed a mark on him, because of that, so that no one who found him would kill him.
The start of worship or drifting away from God?
The last verse of this chapter reads:"At that time people began to call on the name of the Lord." This is mentioned after we get a list of the lineage of Cain ending with Lamech's confession that he killed because somebody had hurt him. Taking justice into his own hands claiming he had the right to do so because God had forbidden to kill Cain. And the birth of a third son to Adam and Eve.
My initial thought was that this must have been some kind of worship. But when you look at the thing that were mentioned, you can also draw the conclusion that they started to feel the effects of drifting away from God because of their behaviour. The next chapter leads up to the flood, so that conclusion might not be so far fetched.