| Quote #1 She walks in beauty, like the night |
The opening simile of the poem compares the unnamed woman to vast and intangible things, like "night" and "starry skies." Why can't he just compare her to a flower, or to something that we can wrap our minds around more easily?
| Quote #2 And all that's best of dark and bright (line 3) |
If you thought "night" and "starry skies" were abstract ideas, that's nothing. In this line, the speaker relates her beauty to "the best of dark and bright." How can you have a "best" (or worst) of darkness or brightness? We're not used to making value judgments about things as abstract as light and dark.
| Quote #3 Thus mellow'd to that tender light |
More vast and intangible things! The woman now seems to almost be casting a gentle glow ("tender light"). Her glow is much better than daylight, though – "day" is described as "gaudy," or over-bright and garish, by comparison.