ANSWER: The book of Luke, chapter 2, is the only place in the entire New Testament where the details of the birth of Jesus and the angels that appeared are recorded. The book of Matthew records events such as the visit of the Magi and the fleeing of Mary and Joseph into Egypt. These events, however, took place several weeks after the actual birth of Jesus.
Much of Western culture depicts the birth of Jesus and the rejoicing of angels of his arrival as occuring in December. An accurate chronology of the New Testament, however, which correlates Biblical, historical, climatic and other facts proves this assumption to be grossly incorrect. The birth of Jesus took place in the fall of 5 B.C. sometime between August 27 and September 9. Given the symbolism of God's feast day known as the Feast of Trumpets, his entrance into the world likely took place on September 2.
The Bible states that "a multitude of the heavenly host (angels)" (Luke 2:13) were visibly seen by shepherds shouting for joy over the birth of the Lord. How much is a "multitude?" Scripture does not say. If, however, we take Daniel 7:10 and Revelation 5:11 literally, then at least 100 million righteous angels serve the Eternal.
How many of all the righteous angels in existence were allowed to show themselves in the sky above Bethlehem? Although many of them appeared, it seems unlikely that every righteous spirit in existence could have visibly and distinctly manifested themselves in such a relatively small area.
Scripture, unfortunately, also does not reveal how many shepherds heard the angels rejoice over Jesus or how many sought out his location in Bethlehem.
One a final note Nativity scenes, which usually portray Jesus in a manger, etc. promote several concepts that are not Biblically accurate. One of these inaccuracies is that angels were either standing quite near or fluttering close over where our Savior was born in Bethlehem.
The Bible states that after angels shouted for joy they quickly went back up to heaven (Luke 2:13 - 15). It was only as they were leaving that shepherds made the journey into Bethlehem to find where Jesus was staying. There is no proof these spiritual messengers were as close to the Lord as Nativity scenes show them.