"Ihr Kinderlein, Kommet" (O Come, Little Children) is a beautiful little German Christmas Carol.
Ihr Kinderlein, Kommet - this Wikipedia link has info, the dots, lyrics & audio. The poem, written by Christoph von Schmid in 1798, was put to music by Franz Xaver Luft in 1837, but the little melody we know was 1st written in 1794 by Johann Abraham Peter Schulz and published together with the poem in 1832.
It's Christmas Thread - Grandpafiddle posted a wonderful video with children singing "O Come, Little Children" (English lyrics) here!
I believe it's part of Suzuki Book 1, but here is a VIOLA play-along video - GREAT for beginners!
...you all know there's more!