How we cite our quotes: (line)
Quote #1
The weariness, the fever, and the fret
Here, where men sit and hear each other groan;
Where palsy shakes a few, sad, last grey hairs,
Where youth grows pale, and spectre-thin, and dies; (lines 23-26)
Death and age are the defining features of life, but the nightingale does not have to deal with them. (We don't find out until later that he thinks the nightingale is immortal). In this passage, the speaker is telling the bird how things are in the "real" world. His attitude is ridiculously pessimistic.
Quote #2
Darkling I listen; and, for many a time
I have been half in love with easeful Death,
Call'd him soft names in many a musèd rhyme,
To take into the air my quiet breath; (lines 51-54)
As he stands in the dark forest, smelling the plants and so on, he thinks, "This would be a nice time to die." Huh?! He says that he has whispered soft poetic verses to death, as if it were a lover he were trying to woo. In these moments of peace, death seems like an "easeful" power to bring rest and relief.
Quote #3
Now more than ever seems it rich to die,
To cease upon the midnight with no pain,
While thou art pouring forth thy soul abroad
In such an ecstasy!
Still wouldst thou sing, and I have ears in vain—
To thy high requiem become a sod. (55-60)
This is one of the poem's most intriguing passages, because we're not sure why birdsong would suddenly lead him to imagine his own death. Maybe it's just because he wants the nightingale to sing his funeral song, or "requiem." We don't think this is such a good reason to die, but, hey, to each his own.