Analysis of Why, Why Repine

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.