Anyway, here's the rest of Genesis 4.
19 Lamech married two women, one named Adah and the other Zillah. 20 Adah gave birth to Jabal; he was the father of those who live in tents and raise livestock. 21 His brother’s name was Jubal; he was the father of all who play stringed instruments and pipes. 22 Zillah also had a son, Tubal-Cain, who forged all kinds of tools out of bronze and iron. Tubal-Cain’s sister was Naamah.So, first of all, marriage is not between one man and one woman. It is rather unlikely that these occupations various occupations are entirely hereditary. And whatever being avenged seven times means, being avenged seventy-seven times is even stranger. Lamech took revenge on his attacker it seems. He gets away with it, but anyone who tries to get revenge on him will be in deep doo doo. What is the moral or theological significance of this? The conclusion seems to be that whoever commits murder first gets away with it, and anyone who tries to punish them is the real criminal. Contrast that with what we are usually taught to think about the Ten Commandments.
23 Lamech said to his wives,
“Adah and Zillah, listen to me;
wives of Lamech, hear my words.
I have killed a man for wounding me,
a young man for injuring me.
24 If Cain is avenged seven times,
then Lamech seventy-seven times.”25 Adam made love to his wife again, and she gave birth to a son and named him Seth, saying, “God has granted me another child in place of Abel, since Cain killed him.” 26 Seth also had a son, and he named him Enosh.At that time people began to call on the name of the Lord
Apparently Adam hasn't gotten any for a few years, but now he does and he gets another son and a grandson. And all this time, it seems, people have not been worshiping God. Now all of a sudden they do.
So, these stories continue to be both muddled and ridiculous. (Again, where are all these wives coming from?) Their significance as moral instruction, theology or cosmology is also entirely obscure when it isn't offensive. It doesn't really matter, however, because this material is never read in church and preachers in general ignore it. Christians never have to think about it. People who claim to be fundamentalists or biblical literalists inevitably cherry pick the passages they pay attention to.