Genesis 4:22
And Zillah, she also bare Tubal-cain, an instructer of every artificer in brass and iron: and the sister of Tubal-cain was Naamah. And Zillah, she also bare Tubal-cain, an instructer of every artificer in brass and iron: and the sister of Tubal-cain was Naamah.
The fourth chapter of Genesis tells the whole story of the first family after the fall and is to be read carefully, showing Cain as a tiller of the ground and Abel as a keeper of sheep, with tilling the soil as God's appointed healthful employment of man's physical powers. The mention of Tubal-cain marks one step in the dark history of Cain and his descendants after Cain withdrew from his father's household and went out from the presence of the Lord, casting away the promise of the restored Eden to seek possessions and enjoyment in the earth under the curse of sin. His descendants became distinguished in mere earthly and material progress and city-building civilization, standing at the head of that great class who worship the god of this world, but they were regardless of God and in opposition to His purposes for man.
The verse shows the beginning of metalworking skill that grew into inventions of art and human skill greater than those known today, using the great gifts God had given men with gold and silver in abundance, as the long-lived race constantly sought to exceed one another in devices. That setting is contrasted with those who remained faithful to God and lived among fields and hills, where labor, study, and meditation helped them learn of God and teach their children. Enoch separated from Cain's descendants because of their increasing wickedness.
Cain had merited death for his crimes, yet his life was spared to give opportunity for repentance. Led on by Satan, he lived only to harden his heart, to encourage rebellion against divine authority, and to become the head and tempter of a line of bold, abandoned sinners whose example and influence exerted demoralizing power. The Lord was forgotten, violence filled the earth until it became corrupt and filled with violence so as to call for its destruction, and men devised how to contend with heaven and gain possession of Eden. Fifteen centuries after the sentence on Cain the fruition of his influence and example appeared in the crime and pollution that flooded the earth, until those greater arts were destroyed in the Flood.
Sparing the first murderer presented before the whole universe a lesson bearing on the great controversy, illustrating what would have resulted from permitting the sinner to live on forever in rebellion against God, since the forbearance of God only made the wicked more bold and defiant. This makes manifest that the sentence of death pronounced on the fallen race for transgression of God's law was both just and merciful, for the longer men lived in sin the more abandoned they became. The divine sentence cutting short a career of unbridled iniquity and freeing the world from the influence of those hardened in rebellion was a blessing rather than a curse.