Beowulf's defeats of Grendel and Grendel's mother establish him as a hero because he did it to save his people, rather than for his own glory. Beowulf is brought from his homeland to Heorot as an aegis for Hrothgar's people. This illustrates the point that he was willing to put himself at risk because he fought the monster with his bare hands and put himself in peril just for the sake of saving others.
"I hereby renounce sword and the shelter of the broad shield, the heave war-board: hand-to-hand is how it will be, a life-and-death fight with the fiend. Whichever one death fells must deem it a just judgment by God." (Heaney lines 436-441).
Grendel had obfuscated Heorot for twelve years and had killed many with his mighty strength. Beowulf knows that by going into a melee with the evil monster Grendel, he is endangering his own life. He also knows, however, that if he dies during the battle it will have been for a just cause because he was saving his people. Beowulf not only fights Grendel but also Grendel's mother. Grendel's mother comes back to Heorot to get revenge on the people who killed her son. Beowulf courageously runs to the rescue when his people are in need. This is another instance in which Beowulf knows that he is putting himself in danger for the sake of others.
" I ask you to recall what we said earlier: that you, son of Halfdane and gold-friend to retainers, that you, if I should fall and suffer death while serving your cause, would act like a father to me afterward. If this combat kills me, take care of my young company, my comrades in arms" (Heaney 1475-1481).
Even though