Analysis of A Symbol

Hurrying for ever in their restless flight
The generations of earth's teeming womb
Rise into being and lapse into the tomb
Like transient bubbles sparkling in the light;
They sink in quick succession out of sight
Into the thick insuperable gloom
Our futile lives in flashing by illume--
Lightning which mocks the darkness of the night.

Nay--but consider, though we change and die,
If men must pass shall Man not still remain?
As the unnumbered drops of summer rain
Whose changing particles unchanged on high,
Fixed, in perpetual motion, yet maintain
The mystic bow emblazoned on the sky.