Suddenly he sang across the trenches,
vivid in the fleeting hush
as a star-shell through the smashed black branches,
a more than English thrush.

Suddenly he sang, and those who listened
nor moved nor wondered, but
heard, all bewitched, the sweet unhastened
crystal Magnificat.

One crouched, a muddied rifle clasping,
and one filled grenade,
but little cared they, while he went lisping
the one cleat tune he had.

Paused horror, hate and Hell a moment,
(you could almost hear the sigh)
and still he sang to them, and so went
(suddenly) singing by.

Humbert Wolfe

http://www.poemhunter.com/poem/a-thrush-in-the-trenches/