The poem describes Beowulf as battle-brave, a strong warrior who had the strength of thirty men. Beowulf was able to undergo the quest of defeating Grendel because he was the only courageous and bold man in his day who was strong enough to challenge Grendel in a battle.
The evidence of his mightiness can be seen in the fact that he defeated Grendel and put him to death. When Grendel's mother also came to avenge his death, Beowulf also defeated her.
