The poem - based on a mythological story of Apollo living as a mortal for a year, working as a farm hand, but alluding to Christ - was written in the early 30´s and set to music in 1939, performed for the first time in 1940. Gullberg added a few lines to it, as a comment to the Nazi aggressions:
Ej för de starka i världen, men för de svaga.
Ej för krigare, men för bönder som plöjt
sin jordlott utan att klaga, spelar en gud på flöjt.
Det är en grekisk saga.
Not for the strong in the world but for the feeble.
Not for the warlike, but for the humble
who till the soil without a grumble
a god plays on a flute.
It is a Grecian fable.
You can find a pdf with the entire lyric in English here.
This is a very classy performance by The Swedish Radio Symphony Orchestra, the Swedish Radio Choir, conductor Esa-Pekka Salonen. If this doesn´t melt your heart, I don´t know what would. If you want more Larsson, I can recommend his "Pastoralsvit" (= Pastoral Suite), another classic.
(on youtube by Classical Music)