"Lulajze, Jezuniu" is a pretty, haunting Polish Christmas carol that dates back centuries. For Christmas, my church choir sang it. It's been translated into English a few times, but I made a few tweaks to better fit the music and our choir. Our choir accompanist improvised his own arrangement and put in short preludes and interludes. The second verse highlighted the voices of a mother and her two young daughters. It ended up being very nice, even with just an amateur choir performing it. Our music director said it was the loveliest number of the Christmas service.
If you'd like to add a new carol to your Christmas library, here is the version we used. On the second and third verses, I indicated with all caps which syllables should have two notes sung to them for a pleasing rhythm.