Man continues his descent into sin, and separation from God. Quickly, anger and jealousy lead to the first murder, as Cain comes against Abel. And it continues from there until the time of Noah, when mankind was so wicked and self-serving that God could no longer stand it. But let’s backup and address a few questions.
What was so wrong in Cain’s offering? Why did it not please God? Some suggest that it was because Cain brought grain as an offering. This cannot be the real issue though. In the law of Moses and the sacrificial system of Israel, they were instructed to bring grains and fruit, oils and nuts as offering at different times and for various reasons. Obviously God was not offended by such an offering. Read it again. Cain brought “some” of the fruit of his crops; Abel brought fat portions from the firstborn of his flock. Now we see the problem. Cain did not bring the best of his harvest or the first gleanings; he brought what was left, what he felt like bringing. Cain kept the best for himself and sacrificed to God almost as an afterthought. That was how he offended God. Cain goes on to show that his thoughts and desires center on himself and not on God when he becomes so angry that he decides to kill his own brother.
We see this again in chapter 6 with the description of mans sinfulness. There is speculation and disagreement over the meaning, or implication, of “sons of God” and “daughters of man”. In places the term “sons of God” seems rather unquestionably to mean angels (such as Job 1-2). From this many believe the account in Genesis means that angels were intermingling with human women. I am not convinced of that interpretation, but prefer the understanding that this indicates that men followed their own desires, selfishly and without regard for right and wrong, especially in their relations with women. It could even indicate that the righteous and faithful line of Seth were marrying the hedonistic daughters of Cain, and were being led into sin by them.
Lamech’s bold and boastful claim finds its reverse in Jesus’ answer to Peter. In punishing Cain by casting him out to wander the earth, God also promised to protect him and to avenge him seven times over if anyone harmed Cain. Lamech (Cain’s descendant) told his two wives (perhaps giving support to my understanding of chapter 6) that he had killed someone for hurting him, and he claimed that if anyone came after him he would be avenged seventy seven times over. Lamech claimed protection and vengeance which God did not give him. When Peter asked Jesus how many times he should forgive a brother who wrongs him, Jesus says seventy seven times. I don’t know if Peter had this incident from Genesis in mind when he asked the question, but I am sure that Jesus intended Peter, and us, to think of Lamech. We have no right to hold a grudge or refuse to forgive. We must resist the ego and self-centered ways of Lamech and instead selfishly forgive all.