In the battle with Grendel's mother, the text states the following concerning God and His role in the fight:
"The son of Ecgtheow would have surely perished
and the Geats lost their warrior under the wide earth
had the strong links and locks of his war-gear
not helped to save him: holy God
decided the victory. It was easy for the Lord,
the Ruler of Heaven, to redress the balance
once Beowulf got back up on his feet."
Through this excerpt, the reader learns that, from the beginning, Beowulf has God's favor. His chain mail saves him from Grendel's mother's terrible grasp, but the reader learns that God decided the victory and Beowulf was the victor of that fight. Later, when Beowulf is recounting the fight to the king of the Geats, he says, "The fight would have ended straightaway if God had not guarded me." Again, the reader sees that Beowulf recognizes that he would not have been successful without God assisting him.
These are important character details for a couple of reasons: one is that the reader sees a part of Beowulf's personality that doesn't often come through--his ability to be humble and give credit to another person, or in this case, a deity. The reader can also deduce that Beowulf is an honorable and just man, as is his cause, because God is backing him up in his endeavors.