There are so many, but one for me is JIMMY NEWMAN by Tom Paxton.

Without writing the whole song its about an injured soldier talking to his friend whom he thinks is asleep. The last line is something like (from memory)

Wake up Jimmy Newman and show them you heard,
I tell 'em you sleep hard but they're shaking their heads
And you've only to open your eyes
And you've only to open your eyes.....


Powerful stuff eh??