Come Now, Savior of the Nations
In the musical tradition of Lutheran Leipzig, Advent was a season in which musical offerings were restricted. Hence Bach has only a few Cantatas for Advent. His Cantata, “Nun komm, der Heiden Heiland” (BWV 62) is based on Luther’s German hymn, itself dependent upon the fourth century Catholic Gregorian chant, “Veni, Redemptor Gentium.”
The opening chorus pleads: “Come now, Savior of the nations/acknowledged child of the Virgin//the whole world marvels/that God ordained Thee such a birth.” Here is a link to a performance by John Eliot Gardiner and his Monteverdi Choir.