Luke is quite specific about the circumstances surrounding Jesus birth:
1. When was Jesus born? Luke 1:5 states that Herod the Great was the king at around the birth of Jesus. Since history dates the death of Herod at around March or April 4 BC, then Jesus must have been born before that date. December 25 was not his exact birth date, but was assigned by the Church later on (more on this on a separate AskTM question).
2. Luke mentioned that the Roman emperor Caesar Augustus ordered a census of the whole world, i.e. the Roman empire. We now know that this is inaccurate since there was no such universal census taken at around this time. The closest is that held in Palestine when Quirinius was governor of Syria (also mentioned by Luke), but which was around 6 AD.
Biblical scholars believe that the census is a literary device used by Luke to associate Mary and Joseph, residents of Nazareth, with Bethlehem, the town of David. Also, every time there is a Roman census, there is usually opposition by the people since this is a recognition of Roman authority over them, and caused a lot of inconvenience. Luke wanted to tie Jesus birth to a time of political disturbance associated with a census.
Such political disturbances were one of the triggers for the revolt of Judas the Galilean, and Luke wanted to show that Joseph and Mary (who were both Galileans) were obedient to Rome. Jesus and the Christians have no political ambitions.
Augustus is also known at that time as the peaceful Savior, so this serves as a contrast to Jesus who brings the real peace (see the message of the angels) and is the real Savior.
3. Luke establishes that the procedure is for everyone to go to the city of his ancestry and Joseph went to Bethlehem, the city of David; even though Jerusalem is traditionally regarded in the Old Testament as the city of David.
Luke wanted to connect the birth of Jesus in Bethlehem with what is written in Micah 5:2: "But you, O Bethlehem Ephrathah, who are little to be among the clans of Judah, from you shall come forth for me one who is to be ruler in Israel."
Joseph and Mary were living in Nazareth at that time and had to travel southward to Bethlehem which was about 100 kilometers away. Using an animal to travel (at about 3 to 4 kph), and considering Mary is pregnant which would have added to travel time, this distance would have taken about 7 to 9 days. By the way, the bible does not mention that Joseph and Mary used a donkey, although they certainly used an animal to travel. It could have been an ass, horse, mule or donkey.
4. Luke’s narrative of Jesus birth is very brief. Luke seems more interested in telling his readers where Mary lay the newborn child - in a manger. The symbolism behind this is not clear. Perhaps it lies in the contrast between the extraordinary titles given to the child and his poverty. God is thus revealed in a paradox.
A manger is a feeding-trough, crib, or open box in a stable designed to hold food for livestock. In Bible times, mangers were made of clay mixed with straw or from stones cemented with mud. Some mangers were cut from a limestone block or carved in natural outcroppings of rock, because livestock was sometimes stabled in a cave. (Thus, there is some tradition that Jesus was born in a cave).
5. There were shepherds out in the field. Shepherds were despised people at the time of Jesus. They were suspected of not being very scrupulous in matters of ownership; and so, their testimony was not admissible in court. They had the same legal status as the tax collectors. In view of what Luke says later on in his gospel regarding the preference of Jesus for tax collectors and sinners, the choice of the shepherds as the first beneficiaries of God's revelation in Jesus becomes quite significant.
Sources: Nil Guillemette, SJ, Kingdom for All (St. Paul’s Publications, 1988) and Microsoft Encarta Encyclopedia.
