Answer:
These lines are important for the Geats as these are the last words of Beowulf before his death and appoints the next King of Geatland. These lines also reveals that legacy is important. In these lines, Beowulf is talking about to pass on his armor-shield to his heir, which he do not have.
Step-by-step explanation:
Lines 137-140 of the epic Beowulf notes the few of the last words of dying Beowulf. These lines are important for Geats as Beowulf is about to die but has no heir of his own flesh. In his last speech he mourns the fact that he left Geats with no heir to whom he could pass on his battle armor. He remembers the fifty years of his service as a King to Geats, the years in which he has fought many great battles and protected his people from enemies.
In his last speech, Beowulf appoints Wiglaf, a retainer who came forward to help Beowulf in his fight with the Dragon, as a next King of Geatland.
These lines also sheds the light on importance of passing down the legacy to the next generation. Beowulf died without having an heir and thus is talking about to have someone to which he can pass his armor-shield.