Final answer:
The waters surrounding Grendel are depicted with dark and sinister imagery, which resonate with Christian symbolisms of death, purification, and salvation. The passage hints at the concept of battling and overcoming evil, echoing the themes of biblical stories and the salvationist intent found in Christian tradition.
Step-by-step explanation:
The images used to describe the water Grendel is in are often dark and sinister, reflecting the dangers that lurk within it. In Christian iconography, water can symbolize both death and purification, and its use in the passage around lines 528-533 of Beowulf likely evokes this dual nature. The Christian concept evident here includes the theme of salvation that is frequently represented by water in Biblical stories, such as with Noah's Ark offering deliverance from the Deluge, or the story of Moses leading his people across the Red Sea.
Additionally, Christian symbolism is expressed through the notion of overcoming evil as demonstrated by the battle against dragons or serpents, with Grendel's watery lair akin to these biblical challenges. This echoes the idea of Christ's battle against sin and death, suggesting that the hero's action has a salvationist intent, much like St George slaying the dragon.