Unferth and Hrothgar do not want to eat the apples because Hrothgar says that the apples are bewitched.
When Beowulf gives Hrothgar an apple, Unferth and Hrothgar will not eat the apples due to superstition. Hrothgar describes it as “witch-work.”
“An old witch spat her teeth out there,” he muttered. “They were bad teeth—green and red and rotting. They grew into apple trees. Nobody in his right mind would eat fruit like that.” (ch 5)
Of course, Beowulf has no problem eating the apple. Unferth suggests that only a wicked person could eat bewitched apples and be all right, and Beowulf laughs. Beowulf tells Unferth that bad does not always come from bad.
This incident demonstrates how Beowulf is quick-wittted and has common sense, and is able to difuse a situation. However, it also shows that Unferth does not like him.