Elvis Costello's concert Sunday night at Wolf Trap was a test of endurance: His three-hour set included a 10-song encore and a 13-song country mini-set with guest Emmylou Harris.

But even with such a lengthy nod to Nashville, the night was typical Costello: earnest vocals, tightly executed arrangements as his backing band, the Imposters, followed his every speeding guitar riff, and a casual sense of humor. In introducing Merle Haggard's "Tonight the Bottle Let Me Down," he joked that earlier in life his mission was "to rid the world of alcohol -- by drinking it!"

While Costello's fervent energy built momentum through his set, some of the evening's best songs were exercises in restraint. He, Harris and bassist Davey Faragher clustered around a single microphone to sing the Stanley Brothers' "Gathering Flowers for the Master's Bouquet," accompanied solely by Costello's guitar and a violin. And Costello's mellow vocals harmonized seamlessly with Harris's on a cover of Chris Hillman and Gram Parsons's "Wheels."

Not surprisingly, there were several tributes to Parsons, Harris's partner early in her career, from a tender duet of "Love Hurts" to a majestically melancholy version of the Rolling Stones' "Wild Horses," which Parsons recorded with his Flying Burrito Brothers. But even in a set so packed with covers, Costello's own material was the most memorable, as he closed the night with his passionate antiwar song "The Scarlet Tide," with a haunting plea to "bring the boys back home."

-- Catherine P. Lewis

Elvis Costello delivered a three-hour set with a 10-song encore Sunday at Wolf Trap.Country singer Emmylou Harris was the evening's guest for a 13-song nod to Nashville.