Composer Harold Farberman created the “Three Letters” song cycle to be unveiled Saturday by the Cambridge Symphony Orchestra. (Photo: bard.edu)

The concept behind the May 19 performance of the Cambridge Symphony Orchestra is intriguing on its own: letters by soldiers from the Civil War, World War II and the Vietnam War set to music by composer (and, as of 1951, the youngest-ever member of the Boston Symphony Orchestra) Harold Farberman.

But this performance of the “Three Letters” song cycle is also its world premiere, and of a work commissioned by the orchestra.

“From time to time we commission work, but it’s expensive,” said Carol Thomas, publicist for the community music organization, noting the last commission from the orchestra was in May 2010. In this case the topic called out, and the idea was decided last summer.

“It’s an important issue in our community, and that was the feeling of our board and artistic director,” Thomas said.

Soprano Rochelle Bard and baritone Graham Wright will bring to life the voices of servicemen and women, and music director Cynthia Woods is also bringing in celebrated pianist Jonathan Bass to join the orchestra on Maurice Ravel’s “Piano Concerto for the Left Hand,” commissioned by the pianist Paul Wittgenstein after he lost an arm in World War I. He used the concerto to continue his career as a concert pianist.

The concert will benefit the Disabled American Veterans charity, which will get a portion of ticket revenue and collect direct donations, and spotlight its work through representatives and literature in the lobby. There will also be lobby space for other nonprofits supporting veterans and their families, including Fisher House Boston, Helping Hands: Monkey Helpers for the Disabled and the Metro Boston Recovery Learning Community.

This concert is supported in part by grants from Cambridge Savings Bank and the Cambridge Arts Council, which gets support from the Massachusetts Cultural Council.

The orchestra’s Benefit Concert for Disabled Veterans is at 8 p.m. May 19 at Harvard University’s Sanders Theater, 45 Quincy St., Cambridge. Advance tickets are $15 for adults and $12 for seniors and students via CambridgeSymphony.org or $20 for adults and $15 for seniors and students at the door.