How many people were in the world when the city of Enoch was founded (Gen 4:17)? How did Cain get a wife?

Evidently there were more than the ones specifically named in the text so far. After all, Cain had a wife, who would evidently have to be a near relation (a sister or a niece). We are specifically told in Gen 5:4 that Adam “begat sons and daughters.” Moreover, one must bear in mind that Adam was 130 when Seth was born (5:3), and that he lived another 800 years. Assuming that people aged very slowly then (as opposed to living out 800 years in extreme decrepitude), then both Adam and Eve could have been parents of hundreds of children. If Adam and his antediluvian progeny were typical, then each of those children could also have many children, so that the world could have many thousands of people in it after just a few hundred years, and not all of them would be near relations, either. It is not even clear that Seth, who was born when Adam was still a young, virile 130, was born after the incident with Cain and Abel, although I expect that was what the narrator intended, since that is the order in which the narrative proceeds. But if indeed Seth and others were born before Cain killed Abel, which is possible, then Cain might have had any number of cousins to live with the town of Enoch in the land of Nod.

What is the significance of Cain’s progeny and how they are described (Gen 4:17-24)?

First of all, they founded the first named city; note that cities, particularly cities of the east such as Babylon and Nineveh, were often associated with sin. Lamech was a murderer, so the iniquity did not leave the family. Another detail worth noting is that, if Jabal had been the original tent-dwelling nomadic herdsman—thus taking Abel’s place—then his ancestors, going back generations to Cain, must have been hunter-gatherers.

Is it not odd that there were two Enochs (Gen 4:17 and 5:18) in early times?

This is only the first of many instances of names with many bearers in the Bible. There are two Lamechs in the two different lines as well. There seems little reason to find significance in this particular juxtaposition. There are two or four Enochs in the Bible, depending on whether one counts “Hanoch” as the same name (the Septuagint renders them the same). The name means something like “initiated, inaugurated, trained.” Both men called “Enoch” might well have been initiated in the ways of their fathers.

How can we draw an interesting comparison between Lamech (Gen 4:18-24) and Enoch, the descendant of Seth (Gen 5:18)?

Of some little interest is the fact that Enoch was the great-great-great grandson of Seth, just as Lamech of the same number of generations removed from Cain. So in the fifth generation after Cain, there is a murderer (Gen 4:23); while in the fifth generation of Seth, when “men began to call upon the name of the Lord”(4:26), there is a man who walked with God and is caught up into heaven without dying (5:24).

Was Lamech the first polygamist (Gen 4:19)?

Perhaps: he was the first one recorded. That this was frowned upon even in OT days is arguably shown in Gen 2:24: “Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.” Other texts show that the better way, at least, was to have only one wife: “Neither shall he multiply wives to himself” (Deut 17:17; one of the rules for the future kings of Israel). Similarly, “A bishop then must be blameless, the husband of one wife” (1 Tim. 3:2). This meant that in those times, as with slavery, polygamy was tolerated by God, probably in a concession to the inevitable practices of primitive man.

Three sons of the murderer Lamech, himself a descendant of the killer Cain, are credited with founding various useful arts (Gen 4:20-22). What are we to make of this?

The irony is strange indeed. Cain’s descendant Lamech both begets children who give the world useful arts and himself commits the world’s second recorded murder. Jabal was (after Abel) the original nomadic herdsman; Jubal, the original musician; and Tubalcain, the original blacksmith. It is hardly as if such arts are frowned upon in themselves in the Bible; David was a shepherd and a musician, and as a general, a user of the blacksmith’s arts. So it is certainly striking that these origin stories are sandwiched between two murders. This is probably not accidental. Probably, in keeping with the theme of not seeking forbidden knowledge (Gen 3) or building towers to heaven (Gen 11), we are to infer that such practices, however fine they might be, pose a danger in the form of pride.

Is it true that Lamech is not only not punished by God, he is allowed to boast (Gen 4:23-24)? Why?

It is true. After “my wounding” which was “to my hurt,” he has slain a “young man.” From the sound of this, it is at best self-defense, but it looks like manslaughter. It is entirely possible that God permitted this because it was in self-defense (which is permitted in the Mosaic code). But I suspect that, especially due to his self-comparison to Cain, this was a murder; moreover, it was not “an eye for an eye,” but rather it was a life for a “hurt.” But if it was indeed a murder, then why did God allow the crime to go unpunished? It seems that he had washed his hands of Cain and his progeny: he had turned his face from Cain, and unlike Seth, that line did not seem to be calling upon the name of the Lord. It is worth noting that not many generations would succeed this one before God would destroy all of humanity in the Flood. Lamech’s violence and arrogance well exemplify the “wickedness of man” that doubtless even by that time had become “great in the earth” (Gen 6:5). If Lamech was long-lived, then probably he was killed in the Flood.