The version of the spiritual Go Tell it on the Mountain recorded by Peter, Paul and Mary; mentions Jesus but is mainly about freedom from slavery. You could rewrite one line to suit the occasion:

Who's that yonder dressed in white,
Let my people go.
Must be the people of the Israelites
Let my people go.

Go tell it on the mountain,
Over the hill and everywhere,
Go tell it on the mountain,
Our Jesus Christ is born.

Who's that yonder dressed in red,
Let my people go.
Must be the people that Moses led
Let my people go.

Who's that yonder dressed in black
Let my people go.
Must be the hypocrites turning back
Let my people go.

The Christmas song version is attributed to John Wesley Work, Jr
(see https://gaither.com/go-tell-it-on-the-mountain-the-story-behind-the-song/)
partial lyrics:

While shepherds kept their watching
O'er silent flocks by night
Behold throughout the heavens
There shone a Holy light

Go, tell it on the mountain
Over the hills and everywhere
Go, tell it on the mountain
That Jesus Christ is born