Genesis 4:16 Cain left Yahweh’s presence, and lived in the land of Nod, east of Eden. 17 Cain knew his wife. She conceived, and gave birth to Enoch. He built a city, and named the city after the name of his son, Enoch. 18 Irad was born to Enoch. Irad became the father of Mehujael. Mehujael became the father of Methushael. Methushael became the father of Lamech. WEB
Some people will ask about Cain’s wife (as will non-believers attempting to discredit the Bible and/or Bible believers) since the only names mentioned at this point are Adam, Eve, Cain and Abel. The first thing to note is that Scripture doesn’t tell us that Cain met his wife in Nod nor if there were any people living there at the time he arrived there. An argument gets made that there were must have been other original inhabitants of earth beside Adam and Eve. The problem with this theory is that Genesis 3:20 tells us that Eve is the mother of all the living therefore anyone living on the earth is a descendant of Adam and Eve. While we don’t know how many children they had, we know from Genesis 5 that they had many. The picture we might have is that Cain and Abel are young but Genesis does not specify when the murder ofAbel takes place. The two of them might be 30 or 50 or even older which allows time for Adam and Eve’s children and grandchildren to reach adulthood. The thought of marrying a a sister, cousin or niece makes us uncomfortable but there is no prohibition against marrying a sibling until Moses comes along. See: https://www.blueletterbible.org/faq/don_stewart/don_stewart_717.cfm or https://answersingenesis.org/bible-characters/cain/creation-basics/ for more.
Genesis 4:19 Lamech took two wives: the name of the first one was Adah, and the name of the second one was Zillah. 20 Adah gave birth to Jabal, who was the father of those who dwell in tents and have livestock. 21 His brother’s name was Jubal, who was the father of all who handle the harp and pipe. 22 Zillah also gave birth to Tubal Cain, the forger of every cutting instrument of bronze and iron. Tubal Cain’s sister was Naamah. WEB
God has instructed Adam and Eve to till the garden and to have dominion and that is starting to show up as humanity takes charge of culture.
The standard for Genesis 1 and 2 is monogamy, i.e., polygamy isn’t in the design. What makes Lamech think that he can have two wives? Things are starting to drift further away from the garden and has continued to do so as later we see Abraham, King David and King Solomon with multiple wives. If there is a silver lining in this, it implies that a relationship with God does not require perfection. For more see Francis Schaeffer’s sermon on this topic: http://blog.faithfellowship.info/wp-content/uploads/2014/11/PDF-The-Weakness-of-Gods-Servants-Schaeffer-No-Little-People.pdf
Genesis 4:23 Lamech said to his wives, “Adah and Zillah! Listen to me! You wives of Lamech, hear my words! I have killed a man for wounding me, a young man for hurting me. 24 If Cain is to be avenged seven times as much, then Lamech seventy-seven times!” NET
Lamech either killed two people or one who was young. He then makes an odd claim that if Cain had 7 fold that he deserved seventy times that. Perhaps his thought process was that since he was justified in his killing (versus Cain killing Abel) that he should be even more protected. Problem is that Cain’s protection came from God so Lamech is presuming an awful lot. Isn’t it often like that – we want God to do what we think is right or good (and are unhappy when He goes in a direction that is against our wishes).
Genesis 4:25 And Adam again had relations with his wife, and she gave birth to a son and named him Seth, saying, “God has granted me another seed in place of Abel, since Cain killed him.” 26 And to Seth also a son was born, and he called him Enosh. At that time men began to call upon the name of the LORD. BSB
We now identified a Cain branch of the family tree and a Seth branch of the family tree. Those in the Seth line are calling on the name of the Lord perhaps implying that there is a side of the family that is righteous and trying to advance the cause of God. Don’t forget, however, that God is still talking to Cain, as well, even if it looks a little half-hearted on the part of Cain. The descendants of Cain are moving out in the world and making things happen but bracketing that is a deliberate, disregard for God. Some have asked if what we see in verse 26 is the beginning of organized religion.
Genesis 5:1 This is the book of the generations of Adam. In the day that God created humankind, he made him in God’s likeness. 2 He created them male and female, and blessed them, and called their name ‘humankind’ on the day when they were created. NHEB
The question of which Torah verse is the most important is one that has been batted around by Jewish rabbis for centuries. It won’t come as a surprise that Deuteronomy 6:4 and Leviticus 19:18 (to love God with our whole heart and our neighbor as ourselves) are at the top of the list but 2nd century sage Ben Azzai selected Genesis 5:1. The reasoning is that this verse makes all of humanity into a single thing – not groups but all of us. It is the idea of brotherhood and it calls us to our intrinsic identity as God centered and oriented beings as our lives don’t work without God.
Genesis 5:18 When Jared had lived 162 years, he became the father of Enoch. 19 Jared lived 800 years after he became the father of Enoch, and he had other sons and daughters. 20 The entire lifetime of Jared was 962 years, and then he died. 21 When Enoch had lived 65 years, he became the father of Methuselah. 22 After he became the father of Methuselah, Enoch walked with God for 300 years, and he had other sons and daughters. 23 The entire lifetime of Enoch was 365 years. 24 Enoch walked with God, and then he disappeared because God took him away. NET
What is fundamental as you read through the verses is that all die with the exception of Enoch at verse 24. In this string, Enoch walked with God, as did Adam and Noah in Genesis 6:9, and was taken away. (Ezekiel also got took. Catholics will extend this to Mary). It is interesting that Jesus dies and was resurrected but Enoch doesn’t die. There are a number of good online discussions about this. Start by searching “Enoch and rapture”.