Adam again had intercourse with his wife, and she gave birth to a son whom she called Seth. “God has granted me another offspring in place of Abel,” she said, “because Cain killed him.”
and named him Noah, saying, “This one shall bring us relief from our work and the toil of our hands, out of the very ground that the Lord has put under a curse.”
unlike Cain who belonged to the evil one and slaughtered his brother. Why did he slaughter him? Because his own works were evil, and those of his brother righteous.