The Polní mše, H. 279 (English "Field Mass") is a Czech language choral work from 1939 by Bohuslav Martinů. It was written to honor Czech volunteers fighting in the French army. The libretto does not follow a traditional mass text but a free libretto written by Jiří Mucha based on Psalm texts and liturgical texts.
References
Field Mass Wikipedia(Text) CC BY-SA