The King of the Danes had saved Beowulf's dad's life many years ago. So Beowulf believes that is important to repay this debt. So when Beowulf hears of the problem the Danes are facing with Gerndel, he steps up the plate. The Hero Beowulf is willing to fight Grendel to this community. This will also repay the kindness that the Danes showed Beowulf's father.