One example of personification in "Beowulf" comes when Beowulf describes sea monsters as "vengeful creatures, seated to banquet at bottom of sea." By comparing the hungry sea creatures to humans ready for a meal, he is using personification, the attribution of human qualities to non-human things.
The narrator of Beowulf reserves much of his personification for weapons and armor. During the fight with Grendel's mother, the narrator personifies Beowulf's sword: "Then sang on her head that seemly blade / its war-song wild." By comparing the sword to a wild warrior, the narrator underscores the violence of Beowulf's attacks. Later, a helmet is described as being "all haughty with gold." The helmet itself is not haughty, but the narrator ascribes haughtiness to it to accentuate its richness and convey the emotions that the wearer of the helmet might feel.
The narrator of Beowulf also personifies the natural elements. After the battle with Grendel's mother, which takes place underwater, Beowulf swims to the surface and comes back onto shore. The narrator then says that the water, which had been roiled with violence, "now drowsed." This personifies the water as a sleepy person, emphasizing the quiet after the battle and echoing Beowulf's own fatigue after his tiring triumph. Conversely, in describing a great flood, the speaker describes "raging waves," attributing to water the human emotion of anger.