Prelude, Offertory, Postlude format on the tune ALLEIN GOTT IN DER H?. Prelude begins/ends with shepherd music, a setting of the angels song; chorale is developed to full organ via series of continuous short variations. Offertory presents chorale phrases unadorned in L.H. accompanied by running passage in R.H., interspersed with lilting ritornello. Postlude is short toccata.