The Minnesota Orchestra embarks this weekend on a Beethoven marathon that has the ensemble performing all nine symphonies and five piano concertos in 18 days.

That apparently wasn’t enough for about 20 musicians and conductor Osmo Vänskä. They will play a benefit concert for Syrian refugees at 4 p.m. Sunday, Jan. 3, at Our Lady of Grace Catholic Church in Edina.

Principal cellist Tony Ross and his wife, Beth Rapier, who also plays cello with the orchestra, spearheaded the project to aid relief efforts for the estimated 6 million refugees within Syria who have been displaced by civil war that has devastated the country for nearly five years. Many others have fled for Europe and other parts of the world.

“I have this quote from Leonard Bernstein, who said after President Kennedy was shot in 1963: ‘This will be our reply to violence. To make music more intensely, more beautifully and more devotedly than ever before,’ ” Ross said.

He and Rapier are members of St. John’s Episcopal Church in southwestern Minneapolis and have for years done benefits for Habitat for Humanity. They were approached in September by representatives of that church and Our Lady of Grace to see if they could help Syrian relief.

“Because of our work with Habitat, we knew some of what had to be done to put it together,” Ross said.

The program will feature Vänskä playing the Mozart clarinet concerto with a group of 18 musicians. The Minnesota Orchestra brass quintet will perform several selections, and a group of string players that includes Ross, Rapier and concertmaster Erin Keefe will perform the Tchaikovsky String Sextet. “I think it might be his greatest piece,” Ross said.

Our Lady of Grace was chosen because it can hold about 900 people — nearly triple the capacity of St. John’s. Proceeds go to the Minnesota-based American Refugee Committee, which has a subsidiary that works within Syria.

“It’s an unbelievable need,” Ross said. “I’ve been told it’s the biggest refugee crisis since World War II.”