Ett barn är fött på denna dag
(Swedish traditional melody)

You can easily sing this SAATB arrangement as SATB instead; just skip the descant in the second verse.


According to

http://susning.nu/Ett_barn_%E4r_f%F6tt_p%E5_denna_dag
(in Swedish)

this is originally a variant of Martin Luther's "Vom Himmel hoch" (in Swedish, "Av himlens höjd oss kommet 
är").

On
http://susning.nu/Fr%e5n_himlen_kommer_jag_med_bud

there is the Swedish version "Från himlen kommer jag med bud" and Luther's original German lyrics of
"Vom Himmel hoch" (15 verses!)