The opening was more conservative, Bach’s third motet, Jesu, meine Freude, where Ars Nova gave a performance as dramatic as a choral opera. The work tells the story of Jesus not objectively, but from the viewpoint of a believer, who sees hell and heaven and witnesses the agony of the Christ. Mr. Hillier took his group through the ecstasies and the agonies, and at the end–with the solace of “Jesus, my true joy”–their notes were both beautiful and beatific.