In Beowulf, the theme of good vs. evil is introduced in Section 1. What greater conflict does the war between the Danes and Grendel represent?

In the story of Beowulf, the theme of
good vs evil is introduced in Section 1. Descended of one known as Beowulf
Scylding, Hrothgar becomes a king of the Danes, and builds a mead hall, where men join
to visit and celebrate. The sound of "revelry" (rejoicing) angers Grendel, a
human-monster that lives in the fens (swamps).

Section 1
tells of Grendel's heritage: he is a descendant of Cain (son of Adam and Eve), who
murdered his brother Abel, in the book of Genesis in the Bible. Because of Cain's sin,
he is exiled, and Grendel, his descendant, is also exiled from the company of
men.

On kin
of Cain was the killing avenged 
by sovran God for slaughtered
Abel. 
Ill fared his feud, and far was he driven, 
for the
slaughter's sake, from sight of men. 
Of Cain awoke all that woful
breed, 
Etins and elves and evil-spirits, 
as well as the giants
that warred with God 
weary while: but their wage was paid
them!

Grendel is considered
evil, as was Cain (who sired his line), elves, evil spirits, and giants. None of these
is at peace with God.

And so the greater conflict here,
beyond simply good vs. evil, and Grendel vs. man, is God vs. all those creatures who
have "warred" with him. This could be translated to mean God vs. the Devil, or the
powers of darkness.