Here are the words we sang in high school. Don't know if they are public domain or not.

Come ye shepherds, come ye shepherds,
Bring your gifts and let us go
To the village, to the village
in the cold and winter's snow.
There is music in the darkness
as the winds go sweeping by,
and a star is in the sky.
And a star is in the sky.

Ye shall find him, ye shall find him
in a stable mean and poor.
Very softly, very softly
ye shall enter by the door.
Then on tiptoe, then on tiptoe
ev'ry shepherd silence keep.
For a baby lies asleep.
For a baby lies asleep.