NOTES for Gen 4:16-26
The main occupation of Cain's descendants becomes the creation of civilization: they build cities and develop crafts, trade, and art. So is it really necessary to commit fratricide first in order to create civilization? Can civilization be built only on blood, and does it itself require blood?
It is not quite that after all. Perhaps the question is why civilization is created. The answer would seem clear: to make life more comfortable and safer. At first glance, cities, the development of crafts, and the appearance of art all serve precisely these goals. If not for one small episode with Lamech, who boasts that he avenged the injury done to him in such a way that no one would ever again even think of daring anything like it. And here the reverse side of civilization shows through, the side soaked in blood.
It would seem Lamech was not the first to begin. He only struck back. But he struck with all his might, wildly, not in order to defend himself, but in order to kill, to destroy the enemy, to destroy him as an example to anyone who would dare attack. This is no longer self-defense, but vengeance: vengeance not only for himself, but also for Cain, who had had to humble himself and ask God for protection (for someone who, like Cain, considers God an enemy and a merciless judge, such a request cannot but be humiliating).
Self-assertion grounded in force and vengeance - this is the spiritual foundation of fallen civilization. It is no surprise that its history begins with fratricide. It is not hard to guess what its end can be.