The Question and Answer section for Beowulf is a great resource to ask questions, find answers, and discuss the novel.
When Grendel enters Heorot his intent is to kill and consume as many of its inhabitants as possible. Unfortunately, he doesn't know of Beowulf's arrival, and Beowulf is waiting for him. When Beowulf grabs onto Grendel's arm, he is taken by...
Previous warriors had failed in killing Grendel because he could not be killed by steel weapons. The weapons of men were useless. The only weapon Beowulf used was sheer strength..... the power of his hands.
After Beowulf tears Grendel's arm from his body, he returns to the mire where he dies.