Excellent question! Both in Beowulf and in “The Dream of the Rood,” true heroism is associated with a Christian willingness to sacrifice oneself for others – a willingness rooted in devotion to God.
For example, Beowulf demonstrates true Christian heroism through his final battle against the dragon, a battle that results in the deaths of both. As Beowulf is dying, he thanks God for his victory over the dragon. He realizes that he has made a worthy sacrifice of himself by remaining true to his Christian principles, thereby benefitting his people.
Similarly, in “The Dream of the Rood,” Christ himself is presented as a kind of epic hero – a man willing and indeed eager to sacrifice himself so that others (in this case all of humanity) may benefit. Both Beowulf and Christ are “defeated” in a worldly sense (since both die), but each shows, in the process of sacrificing themselves, how easily heroism can be reconciled with saintliness from a Christian perspective.