The fact is, Unferth, if you were truly
as keen and courageous as you claim to be
Grendel would never have got away with
such unchecked atrocity, attacks on your king,
havoc in Heorot and horrors everywhere.

Beowulf, Seamus Heaney (trans.)

Lines 590-594: Beowulf insults Unferth, who claims to be a heroic character, for not doing battle with Grendel. Being heroic and courageous is very important to the story of Beowulf.