09/08/09 Hw Q's Beowulf Part1

When reading the passage from Beowulf I understood the main thing that was going on. What confused me a bit was the religious aspect in all of this. Why is it that Beowulf was asked to go back and kill Grendel's mother? Does this mean that the Anglo-Saxons believed in revenge against all who do evil? What makes me question this is the part in the story when Beowulf goes down to the monster's lair to kill off the mother, then decides to seek revenge on Grendel by killing off all the other monsters in the way. If Beowulf was referred to as a "good guy", then how could he have it in his heart to do bad to others? Especially in the final part when he cuts off Grendel's head. I don't know, but that was the part that I did not understand completely.