The willow dipped its fingers into the stream. The lizard cackled to itself when the girl fell on her face. Personifying nature by giving it human characteristics or motivations is an easy way to liven up the landscape: it adds symbolic depth, jazzes up the descriptions, and gives the reader a little jolt of humor or surprise.
In "Corinna's Going A-Maying," the speaker personifies all over the place, turning the dawn and sun into mythological gods and making the flowers weep. Emphasizing the efficiency and industry of the natural world, the speaker gently scolds Corinna for being so lazy and tells her to look outside for some good examples of getting things done. At the same time, he uses personification to argue that going a-Maying is worthwhile—in fact, just as good as going to church.
By giving the natural world human and godly characteristics, he elevates the spring into a whole alternative system of religion. In other words, don't stay inside with your rosary beads: the birds are out praying and the neighbors are playing. Spring is just as important as Christianity.
Lines 1-2: The dawn is compared to some lovely angel with wings outspread, while the sun is a god. He's still "unshorn" or bald because it's still early in the day and he's not sprouting a lot of beams.
Lines 3-4: Here the dawn is personified into Aurora, a Greek goddess. But is this one of those lounging deities who drinks nectar on a couch and watches Real Housewives of Athens? Not a chance. She's already shaking out the sheets and cleaning up for the new day.
Line 7: We all know how plants get covered in dew at night and turn towards the light. But notice how "bow'd" adds a religious touch to this morning scene. These flowers seem to be worshiping the rising sun (who was compared to a God in line 2).
Lines 10-11: Like the bowing flowers, these birds are as religious as human Christians. They've said their prayers and sung their hymns, in worship of the oncoming day.
Lines 21-22: Despite its busyness, nature is keeping Corinna in mind. The day has thoughtfully kept some dew in reserve for some nice, locally sourced bling.
Lines 25-26: Night, like the sun, is a god. And like the day, he's also thinking of Corinna. Just look at this piece of chivalry: he's willing to linger a little in order to give her more time. What a gentleman.