Final answer:
Beowulf describes Grendel as a descendant of Cain and explains how he and his descendants were punished by God and transformed into evil spirits and monsters.
Step-by-step explanation:
The lines you have quoted are from the epic poem Beowulf. In these lines, Beowulf describes Grendel as being a descendant of Cain, who was punished by God for killing his brother Abel. According to Beowulf, Grendel and his descendants were driven out by God and forced to live in exile, where they transformed into various forms of evil spirits and monsters. They constantly oppose God's will and are repeatedly defeated. These lines highlight the theme of evil and the eternal battle between good and evil in the poem.