The flame flashed forth, light there blazed within, even as of heaven radiantly shines the candle of the sky. He gazed about that house, then turning went along the wall, grasping upraised that hard weapon by the hilt, in ire undaunted the knight of Hygelac. That blade the warrior bold did not despise; nay, he thought now swiftly to requite Grendel for those many dire assaults that he had made upon the Western Danes, far oftener than that one last time, slaying in slumber the companions of Hrothgar's hearth, devouring as they slept fifteen of the people of the Danes, and others as many bearing forth away, a plunder hideous. For that he had given him his reward, that champion in his wrath, so that on his couch he saw now Grendel lying weary of war, bereft of life, such hurt had he erewhile in battle got at Heorot. Far asunder sprang the corpse, when Grendel in death endured a stroke of hard sword fiercely swung; his head was cloven from him. (pp. 58-59)For comparison's sake, here's Heaney's verse translation of the same part:
A light appeared and the place brightenedI'll leave it up to you to decide which version appeals to you most.
the way the sky does when heaven's candle
is shining clearly. He inspected the vault:
with sword held high, its hilt raised
to guard and threaten, Hygelac's thane
scouted by the wall in Grendel's wake.
Now the weapon was to prove its worth.
The warrior determined to take revenge
for every gross act Grendel had committed –
and not only for that one occasion
when he'd come to slaughter the sleeping troops,
fifteen of Hrothgar's house-guards
surprised on their benches and ruthlessly devoured,
and as many again carried away,
a brutal plunder. Beowulf in his fury
now settled that score: he saw the monster
in his resting place, war-weary and wrecked,
a lifeless corpse, a casualty
of the battle in Heorot. The body gaped
at the stroke dealt to it after death:
Beowulf cut the corpse's head off.
(lines 1570-1590, p. 109)