The previous verses were from 2 carols so well known (to me) as to need no comment.
"Good King Wencleslas" and "We Three Kings"
I agree with the other answers.
I thought that children were sent to Sunday school by non-religious parents to give the adults a bit of privacy.
Its a different world, isnt it. In our day everything was organised by volunteers, Sunday School, Guides, GLB (similar to guides but more religious) etc. It was enough for my mother to find 3s 6d a week for my piano lesson. Now everything is commercial, or so it seems.