Although it is a single work in six related parts, Bach’s Christmas Oratorio could be regarded as a compilation of six separate cantatas. Recognizing the fact that Christmas is not a day, but a twelve-day season, the scheme of the Oratorio appoints Part 1 to be sung on Christmas Day, Part 2 on St. Stephen’s Day (December 26th), Part 3 on St. John’s Day (December 27th), Part 4 on the 1st of January to celebrate the Feast of the Circumcision (coinciding with New Year), Part 5 sung on the first Sunday after New Year, and Part 6 on January 6 for the Feast of Epiphany.
Officially designated Weihnachts-Oratorium, BWV 248, the work includes many choruses, chorales, arias, and recitatives that were lifted from previously composed cantatas and “re-purposed” with new texts. Bach scholar Michael Marissen has performed a great service by assembling all of the Oratorio’s libretti into a single volume with parallel German-English text and extensive annotations explaining the biblical and theological references in the text (Bach’s Oratorios, Oxford University Press, 2008). Marissen’s translataion and notes of the entire work are also online here
Below is a recording of a performance featuring an unidentified but talented assembly of musicians.