Cain

Cain is introduced as the firstborn son who works the land, and whose offering of mere 'some fruit' — rather than the first and best — reveals a heart not fully devoted to God.

Cain's line is invoked here as a possible source of the 'daughters of man' — representing the ungodly stream of humanity whose intermingling with the godly line may have accelerated moral corruption.

Cain is invoked as the original model of hatred — John uses him to show that lovelessness has always been rooted in evil, and that goodness in others provokes murderous hostility.

Cain is named as the first in a trio of ancient archetypes — his path represents jealousy curdling into violence, the pattern Jude sees replicated in these teachers' destructive behavior.