Note: This is not about the movie.
Beowulf embodies all the virtues in high regard by the people of the the time: strength -- in his case, superhuman strength -- stamina, skill, courage, daring, leadership, a sense of fair play, and most of all, loyalty to his king. Even his boastfulness, which may be interpreted as mere honesty, is in keeping with the qualities of an Anglo-Saxon hero. Beowulf is the quintessential warrior, and for that harsh period, the exemplar of heroism.
Throughout the course of the epic, Beowulf had many opportunities to demonstrate his strength and battle prowess. The one incident, though, that best shows all the qualities of Old English heroism is when he refuses the offer of Hygd, Hygelac's widow, of the kingdom: "...Beowulf would not for any reason be lord over his king's son..." Instead, he merely assumed stewardship until Prince Heardred came to manhood. Beowulf would become king, but under the proper circumstances and following the rules of succession.
The people of the time believed that death was the ultimate end, and the path therein already dictated by Fate (or, in Anglo-Saxon, Wyrd); hence the term "fatal doom," the end to which men are fated. What mattered was how one faced this end. This idea comes up several times in the epic, either in the narration or in the warrior's boast. The best summary is spoken by Beowulf himself: "Each of us must await the end of this life. He who wishes will work for glory before death."
The Christian influence on "Beowulf" is most significant in the association between Fate/Wyrd and the Will of God. The two are used almost interchangeably. Beowulf, for example, says, "God...shall decide who shall be taken by death." In the context of the text, though, they are distinct concepts. As Fate is a deeply ingrained part of the culture and philosophy of life of that period, this appropriation to Christianity shows how deep the Christian influence had become at the time the poem was set down.