What does Genesis 4:21 mean?
The previous verse told of the life and work of Jabal, Lamech's son with his wife Adah. This verse tells us of his brother Jubal. Jubal became a musician and fathered a line of musicians. Specifically, Jubal and his offspring played the lyre, which is a stringed instrument, and the pipe.It's fascinating to note that just eight generations from Adam, a creative culture is blossoming. Human beings, made in the image of a Creator God, are beginning to express their creativity in one of the areas central to the culture of heaven: music. Unfortunately, this passage also shows that Cain's descendants are continuing his hateful, arrogant rejection of God. Soon, Jabal and Jubal's father will brag about his murder of a younger man. And, he will have the nerve to claim an even greater immunity than Cain was given by God (Genesis 4:23–24).
Genesis 4:17–26 describes Cain's family line after his murder of Abel. While the details are limited, Scripture does mention a few points of concern. Lamech, Cain's great-great-great-grandson not only took two wives, he also bragged about murdering a younger man. This attitude of blatant defiance sets the stage for God's judgment of a depraved earth in the story of the flood in Genesis chapter 6. This passage also describes Adam and Eve's son Seth, born after Cain, who becomes the ancestor of Noah.
The consequences of sin become apparent in chapter 4: envy, arrogance, rebellion, murder, punishment, separation from family, and separation from God. Adam and Eve's firstborn son, Cain, jealously murders his brother Abel and loses everything. Adam and Eve lose them both. Cain's descendants amplify his sinfulness. Still, God provides help for Eve in childbirth and even provides protection for Cain in his wandering. Eve remains a woman of faith, even in her loss. And the sons of Seth, born after the murder of Abel, become a people who proclaim the name of the Lord.