Which parts of this passage contain a biblical allusion?

So lived the clansmen in cheer and revel

a winsome life, till one began

to fashion evils, that field of hell.

Grendel this monster grim was called,

march-riever mighty, in moorland living,

in fen and fastness; fief of the giants

the hapless wight a while had kept

since the Creator his exile doomed.

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,?