Analysis of Resignation

WHY, why repine, my pensive friend,
   At pleasures slipp'd away?
Some the stern Fates will never lend,
   And all refuse to stay.

I see the rainbow in the sky,
   The dew upon the grass;
I see them, and I ask not why
   They glimmer or they pass.

With folded arms I linger not
   To call them back; 'twere vain:
In this, or in some other spot,
   I know they'll shine again.