Lyrics copied from http://www.luma-electronic.cz/lp/c/Cash/cash_america.htm
(But see footnote)

BIG BATTLE
(Johnny Cash)
« © '61 Southwind Music »

"I think, sir, the battle is over," and the young soldier laid down his gun.
"I'm tired of running for cover, for I think the battle is done.
Oh, see over there where we fought them: it's quiet, for they've all gone away.
All left is the dead and the dying. The ground's covered with them today."

"So you think the battle is over and you even lay down your gun.
You carelessly rise from your cover, for you think the battle is done.
Now, boy, hit the dirt. Listen to me, for I'm still the one in command.
Get flat on the ground here beside me, and lay your ear hard to the sand.

"Can you hear the deafening rumble? Can you feel the trembling ground?
It's not just the horses and wagons that make such a deafening sound.
[For every shot fired had an echo, and every man killed wanted life.
There lies your friend Jim McKenny. Can you take the news to his wife?

"No, son, the battle's not over. The battle has only begun.
The rest of the battle will cover the part that has blackened the sun.]*
The fight yet to come's not with cannon, nor will the fight be hand-to-hand.
No one will regroup the forces. No charge will a general command.

"The battle will rage in the bosom of mother and sweetheart and wife.
Brother and sister and daughter will grieve for the rest of their lives.
Now, go ahead; rise from your cover. Be thankful that God let you live.
Go fight the rest of the battle for those who gave all they could give."

"I see, sir. The battle's not over. The battle has only begun.
The rest of this battle will cover the part that has blackened the sun;
For though there's no sound of the cannon, and though there's no smoke in the sky,
I'm dropping the gun and the saber, and ready for the battle am I."

[*The part in brackets was not on the Czech site mentioned above, but it's found at some other lyric sites. I thought it was too good to leave out. Maybe JC recorded more than one version?

[I thought this song sounded older, too, but all the versions I've found on the 'Net were attributed to Cash.]