An English traditional carol, one of many collected by Ralph Vaughan Williams, and published with his own harmonisation in 1919. The words and melody were collected by Vaughan Williams and Cecil Sharp in the West Sussex village of Monk's Gate, from one Harriett Verrall—however, there are earlier sources which claim the so-called "Sussex carol" was being sung in the streets of Dublin many years prior to its final publication.
On Christmas night all Christians sing
To hear the news the angels bring:
News of great joy, news of great mirth,
News of our merciful King's birth.
Then why should men on earth be so sad,
Since our Redeemer made us glad,
When from our sin he set us free,
All for to gain our liberty.
When sin departs before his grace,
Then life and health come in its place;
Angels and men with joy may sing,
All for to see the new-born King.
All out of darkness we have light,
Which made the angels sing this night:
'Glory to God and peace to men,
Now and for evermore—Amen.'
Sources:
The Oxford Book of Carols (Oxford University Press)
http://freepages.genealogy.rootsweb.com/~villages/sussex/monks_gate.htm