Thea in Queensland sends in this First Day of Issue maxicard, cancelled at St. Marys, New South Wales, Australia in 2008. (You can see another card from this series today at Girls Go Postal.) While the card doesn’t specifically say so, I expect that this is the angel who appeared before the shepherds as described in the book of Luke:
And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid. And the angel said unto them, Fear not: for, behold, I bring you good tidings of great joy, which shall be to all people. For unto you is born this day in the city of David a Saviour, which is Christ the Lord. And this shall be a sign unto you; Ye shall find the babe wrapped in swaddling clothes, lying in a manger. And suddenly there was with the angel a multitude of the heavenly host praising God, and saying, Glory to God in the highest, and on earth peace, good will toward men.
A very happy Christmas to you.