American History and Memory
Longfellow is evoking a specific historical memory in this poem: Paul Revere and the Revolutionary War. He does this because the lessons of history can be applied to the contemporary context and be useful in understanding the present, as well as giving counsel and caution for the future. However, Longfellow takes liberties with this historical memory which leads to the question of whether or not complete veracity is necessary in order to achieve these purposes. Revere's story isn't exactly accurate but he is rendered a hero for the ages, and his deed a potent exemplar of courage and right.
Courage and Patriotism
Readers don't get much insight into Paul Revere as a person in this poem, but the one feature that comes across is his courage. Revere knows his task is dangerous and requires the utmost in terms of celerity, discretion, and energy. He comes across as a man impatient to carry out a mission that will save lives and push back against British tyranny, a man who will let nothing stand in his way. Longfellow meant Revere's example to inspire his contemporary readers to remain stouthearted in the face of Southern secession and imminent war.
Time
Time is an interesting construct in this poem. First, the poem concerns events of the 18th century, but has a frame0story (the landlord's tale) that places it in the contemporaneous reader's present, the 19th century. Second, watching and waiting and the sense of interminable anxiety and impatience that dominate the first half of the poem give way in the second half to a breathless, galloping account of time. Third, the evocation of clocks and the dawning of the morn take readers on the journey with Revere, making them feel the sense of hurry and import the famous rider feels. These elements at once emphasize the specificity of time and destabilize it. Longfellow does this to evoke emotion and impress upon the reader the message of the poem.
Action
While the anxiety of waiting saturates the first half of the poem, its dominant theme is action. Revere does what is required of him: he leaps into action and exerts the utmost physical and mental effort to deliver his midnight message. There is a time when watching and waiting are over; there is a time when one must stand up for what is right even if it seems perilous. This is an important thing to keep in mind when contextualizing the poem as one published at the onset of the Civil War.
