Bach wrote the cantata in 1724, his second year as Thomaskantor in Leipzig, for the First Sunday of Advent. The prescribed readings for the Sunday were from the Epistle to the Romans, night is advanced, day will come, and from the Gospel of Matthew, the Entry into Jerusalem. The cantata is based on Martin Luther's Advent hymn in eight stanzas "Nun komm, der Heiden Heiland", the number one hymn to begin the Liturgical year in all Lutheran hymnals. The unknown poet retained the first and last stanza, paraphrased stanzas 2 and 3 to an aria, stanzas 4 and 5 to a recitative, the remaining stanzas to an aria and a duet recitative. Bach first performed the cantata on 3 December 1724, and he performed it again in 1736, adding a part for violone in all movements, after the Thomasschule had bought an instrument at an auction in 1735. Bach's successor Johann Friedrich Doles performed the cantata after Bach's death.
Aria : Bewundert, o Menschen, dies große Geheimnis
Recitative : So geht aus Gottes Herrlichkeit und Thron
Aria : Streite, siege, starker Held!
Recitative : Wir ehren diese Herrlichkeit
Chorale: Lob sei Gott dem Vater ton
Music
The old hymn tune is in four lines, the last one equal to the first. The instrumental ritornello of the opening chorus already quotes this line, first in the continuo, then slightly different in meter in the oboes. Other than these quotes, the orchestra plays a free concerto with the oboes introducing a theme, the first violin playing figuration. The ritornello appears shortened three times to separate the lines of the text and in full at the end. The soprano sings the cantus firmus in long notes, while the lower voices prepare each entry in imitation. Alfred Dürr suggests that Bach was inspired to the festive setting in 6/4 time by the entry into Jerusalem. Christoph Wolff stresses that the instrumentation is simple because Advent was a "season of abstinence". Church music was allowed in Leipzig only on the first Sunday of Advent. John Eliot Gardiner observes about all three extant cantatas for this occasion, also Nun komm, der Heiden Heiland, BWV 61, and Schwingt freudig euch empor, BWV 36, which all deal with Luther's hymn, that they "display a sense of excitement at the onset of the Advent season. This can be traced back both to qualities inherent in the chorale tune itself, and to the central place Bach gives to Luther's words." The first aria deals with the mystery of "the Supreme Ruler appears to the world, … the purity will be entirely unblemished." in siciliano rhythm and string accompaniment, doubled in tutti-sections by the oboes. In great contrast the second aria stresses fight, "Struggle, conquer, powerful hero!", in a continuo line. In a later version it is doubled by the upper strings. Gardiner regards its "pompous, combative character" as a sketch for the aria "Großer Herr und starker König" from Part I of Bach's Christmas Oratorio''. The duet recitative expresses thanks, "We honor this glory", intimately accompanied by the strings. The closing stanza is a four-part setting.
