How does Grendel's lair remind you of hell?

The sea-bottom lair kept by Grendel and his mother is reminiscent of Christian hell in several ways. First of all, it is depicted as being far below the natural land where humans live. This seems to echo the idea that Grendel and his mother, like the creatures that inhabit hell, are morally beneath humanity and God's favor.
Another similarity between Grendel's lair and depictions of hell comes from the presence of smaller monsters that inhabit or guard it. While hell has its demons, fallen angels, and lost souls, Grendel's lair is guarded by droves of sea monsters.
Additionally, in the same way that the love of God is needed to save one from hell, Beowulf, too, is saved from the hopeless fight against Grendel's mother by divine intervention. The epic states that the hero would have lost the battle

had God most holy not awarded the victory,All-knowing Lord; easily did heaven'sRuler most righteous arrange it with justice . . .