Mutability by Percy Bysshe Shelley

We are as clouds that veil the midnight moon;
How restlessly they speed, and gleam, and quiver,
Streaking the darkness radiantly! -yet soon
Night closes round, and they are lost for ever:

Or like forgotten lyres, whose dissonant strings
Give various response to each varying blast,
To whose frail frame no second motion brings
One mood or modulation like the last.

We rest. — dream has power to poison sleep;
We rise. — One wandering thought pollutes the day;
We feel, conceive or reason, laugh or weep;
Embrace fond woe, or cast our cares away:

It is the same! — For, be it joy or sorrow,
The path of its departure still is free:
Man's yesterday may ne'er be like his morrow;
Nought may endure but Mutablilty.