One of the major themes in Beowulf is the political power structures of feudal Anglo-Saxon society. We see at the beginning of the story how the brutal Shield Sheafson came to power, and how his descendants kept his kingdom strong and stable, all the way down to Hrothgar. When Grendel appears and Hrothgar is unable to develop a coherent strategy for Heorot's defense, the kingdom is seriously threatened for the first time. Without Beowulf's heroism in defeating both Grendel and his mother, the Danes would have been in serious trouble. Once that issue was resolved, Hrothgar is forced to deal with the possibility that Beowulf may feel as though he is entitled to rule over the Danes. His queen brings up this possibility earlier, and Hrothgar is forced to toe a fine line in dealing with it.
After Beowulf defeats Grendel's mother in an epic, underwater battle, he returns to Heorot to present Grendel's head to King Hrothgar. At this ceremony, Hrothgar regals Beowulf and all of those present in Heorot with a speech filled with wisdom and advice about the responsibilities of power. Starting on line 1700, Hrothgar praises Beowulf for his tremendous courage in facing Grendel and his mother, and for his offer of friendship, saying, "Beowulf, my friend......In all things you are even tempered and resolute. So I stand firm by your promise of friendship...Forever you will be your people's mainstay and your own warriors' helping hand." Hrothgar immediately follows his praise of Beowulf with a cautionary tale about King Heremod, a former Danish monarch whose brutality and unpopularity eventually lead to his ouster: "Heremod was different, the way he behaved to Ecgwala's sons. His rise in the world brought little joy to the Danish people, only death and destruction." With this line, Hrothgar seems to be appealing to Beowulf's idealism, in the hope that he chooses a different path from Heremod.
While most people would look at Hrothgar's speech on the surface and view it as an outpouring of generosity and advice toward Beowulf, I think there is reason for us to believe that the author is trying to make us skeptical of Hrothgar. Despite the apparent friendly nature of this speech, upon close examination we can see Hrothgar showing us his more calculating side. In fact, the speech follows the same pattern we see from contemporary politicians. By first heaping praise upon Beowulf for his heroic deeds, Hrothgar hopes to disarm him with compliments, and then tries to introduce an element of fear by telling the story of a slain king, which he hopes will give Beowulf pause about laying claim to the Danish throne. He also appeals to Beowulf's sense of humanity and honor by saying he is sure Beowulf will not attempt to emulate Heremod. Although it is certainly honorable for a somewhat enlightened dictator such as Hrothgar to want to keep his people out of tyranny, this does not seem to be his primary concern. His first complaint about Heremod's reign had nothing to do with his treatment of the Danish peasants; it was about his behavior to a previous monarch's children. This clearly indicates what motivations are behind his words, especially when we consider the words of his queen, Wealtheow, who earlier urged Hrothgar to consider abdicating the throne to insure the safety and smooth succession of their sons. To put it frankly, Hrothgar is not really worried for the wellbeing of his people, or for Beowulf, he simply cares about preserving his family's reign over Denmark, a rule which began with a bloodthirsty tyrant in Shield Sheafson. With Beowulf being the most physically powerful warrior in either the Geatish or Danish kingdoms, Hrothgar realizes that he has no chance to stop Beowulf from seizing power, especially after Beowulf makes a surprising alliance with Unfereth, the second most powerful warrior. This leaves the use of his political and persuasive skills as the only recourse to prevent this outcome. In my view, the author could not have possible included this speech with the intention of boosting our opinion of Hrothgar's wisdom. First, Hrothgar's motivation in giving this advice is for the preservation of his family's power. Given that his own sons played virtually no role in the struggle against Grendel, and would therefore be less qualified to protect the kingdom than Beowulf, we can ascertain that Hrothgar is an opponent of meritocracy and is acting for the benefit of his sons at the expense of his nation. Since this type of action is anything but responsible or wise, I think it is in the story to make us skeptical of his wisdom, as well as his character and leadership ability.