It's a lovely tune. Here's an audio-visual file for what it may be worth (starting at the point full SATB is played; before that, there's a gradual layering of voices):

https://youtu.be/VFtkZE9SiuQ?t=45

I tried the Search by Melody function at Hymnary and the dragnet did not reveal anything close.

Thanks. #54 in the Marier Pius X Hymnal, which I believe has been shared. The initials K.A. are for Kalman Antos (acknowledged on fore-page x of the hymnal) (1902-1985) who did the arrangement (https://eo.wikipedia.org/wiki/Kálmán_Antos).

I tried the Search by Melody function at Hymnary and the dragnet did not reveal anything close.

same lol