Say not the Struggle Naught Availeth

SAY not the struggle naught availeth,
   The labour and the wounds are vain,
The enemy faints not, nor faileth,
   And as things have been they remain.

If hopes were dupes, fears may be liars;
   It may be, in yon smoke conceal'd,
Your comrades chase e'en now the fliers,
   And, but for you, possess the field.

For while the tired waves, vainly breaking,
   Seem here no painful inch to gain,
Far back, through creeks and inlets making,
   Comes silent, flooding in, the main.

And not by eastern windows only,
   When daylight comes, comes in the light;
In front the sun climbs slow, how slowly!
   But westward, look, the land is bright!

~ A Poem by Arthur Hugh Clough

Here's my paraphrase, for what it's worth.

Don’t say that the long struggle is of no avail;

don’t say that all your efforts, and all the injuries you’ve sustained, were in vain.
Don’t say that the enemy’s just as strong as ever;
and don’t say that nothing’s changed for the better!

If the things you hoped for haven’t happened, well, maybe the things you’re scared of won’t happen either.
Perhaps over there on the battlefield, now obscured by smoke,
your comrades are chasing the enemy away,
and all they need to ensure victory is that you go and join them.

Look! Those waves don’t seem to be making much headway,
even though the tide’s supposedly coming in.
But far behind you, unseen creeks and inlets are swelling with incoming waters:
the sea really is on the move after all!

Look! The eastern window you’re sitting at
isn’t the only place affected by sunrise;
from there, yes, it’s true, the sun hardly seems to moving up the sky at all—
but cross the room and look through a westward-facing casement: see how the whole landscape’s already flooded with light!