Op. 106, is a composition in four movements by Max Reger in D major for mixed choir and orchestra, a late Romantic setting of Psalm 100. Reger began composing the work in 1908 for the 350th anniversary of Jena University. It premiered simultaneously on 23 February 1910 in Chemnitz, conducted by the composer, and in Breslau, conducted by Georg Dohrn. Reger structured the text in four movements, as a choral symphony. He scored it for a choir of four to eight voices, a large symphony orchestra, and organ. Reger used late-Romantic features of harmony and dynamics, along with polyphony in the Baroque tradition. The last movement is a double fugue, with an instrumental cantus firmus of Luther’s chorale “Ein feste Burg ist unser Gott” as its climax. The biographer Eugen Segnitz considered the work unique in the sacred music of its period, with a convincing musical interpretation of the biblical text and manifold shades of emotion. Paul Hindemith wrote a trimmed adaption that helped to keep the work in the repertory, and organ versions were written to make the work accessible for smaller choirs.