Hi, Allison - I'm having trouble finding lyrics for this, but I did find the first verse and chords at http://www.hift-folksongs.de/TexteFolk/a/allesIst.htm
Maybe these are the complete lyrics - it's described as a "Kanon" - the recording Allison linked to has only these lyrics. Here's another recording: https://www.youtube.com/watch?v=52INtrMXuj8.
This page says it was published in 1942, words by Gerhard Fritzsche; melody by Theophil Rothenberg. The page says it's in a number of German-language hymnals, but not in any that I have.

  Alles ist eitel
  
   
           
  G     D     Em    H7
  C     G    Am/D   G
  
  
  
  G         D      Em        H7
  Alles ist eitel, du aber bleibst,
       C           G   Am   D        G
  Und wen du ins Buch des Lebens schreibst.
   G         D     Em        H7
  Du aber bleibst, du aber bleibst,
  C         G      Am D      G
  Alles ist eitel, du aber bleibst.
   G        D       Em       H7
  Du aber bleibst, du aber bleibst,
       C           G       Am D       G
  Und wen du ins Buch des Lebens schreibst.

My translation:

All is vain, but you remain
And those whom you write in the Book of Life

You'll find notation for the song Here: http://www.vrijeschoolliederen.nl/wp-content/uploads/alles-ist-eitel.pdf

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I found the lyrics to the English song Allison linked to at http://divineoffice.org/adv-w02-mon-mp/
LONG IS OUR WINTER
(Text by Eleanor Walker, 1922–1979; German melody; Arr. by William Ferris, 1937–2000)

Long is our winter
dark is our night
O come set us free
O saving Light.
O come dwell among us
O saving Light.
Amen.

The English-language song can also be found in Worship in Song: A Friends Hymnal, #138. The hymnal describes the song only as "a traditional round." There's sheet music available here (click).

-Joe-