Birthdays are important to many people. The anniversary of the day or our birth has significance to us because it gives us a feeling of significance. I was born on October 6, so I am of a select group of people, roughly 1/365th of the population born on that day. We even sometimes try to determine if any famous people were born on the same day. In my case that includes the inventor of the air brake, George Westinghouse; explorer Thor Heyerdahl; football coach Tony Dungy; actresses Carole Lombard and Janet Gaynor; and architect Le Corbusier. More importantly to me, my granddaughter was born on my birthday.
For some reason some people find it important to determine the date Jesus was born. It almost certainly was not December 25; but when was he born? The Bible offers us some clues, and some complications.
The first step in determining when Jesus was born would be to determine when John the Baptist was born. This is because Gabrielís announcement that Mary would bear a child came in the sixth month of Johnís motherís pregnancy. (Lk 1:26) The assumption (uh-oh, now there is some uncertainty) is that Elisabeth conceived immediately after the announcement that she would have a child. If we donít make this assumption, all bets are off.
Johnís father performed his duties as a priest in the course of Abijah (Lk 1:5). Shortly after such duties, we assume, John was conceived. (Lk 1:23-24) If we can determine when he served we may determine when John was conceived (using our assumption), when Jesus was conceived, when John was born, and when Jesus was born. Since we know he was a priest in the course of Abijah, we can narrow it down considerably.
The priests were assigned duties in the Temple in courses by family. There were 24 courses, each serving a week at a time, twice a year. In addition, everyone worked three weeks in each year (the weeks of Passover, Pentecost, and the Feast of Tabernacles). The first course served at the beginning of the month of Nisan (March/April in the Gregorian calendar). Allowing for Passover and Pentecost, that means that the first time Zechariah could have served would be the week after Pentecost (late May). Some scholars have calculated only from this date, and determined that Jesus was born on or about the first day of the feast of Tabernacles. (John conceived in May; six months later is Hanukkah in December; nine months after that is September/October and Tabernacles.) That is very good, assuming the events in Luke 1 take place during the first course of Abijah.
But what if John was conceived after the second course of Abijah? That takes place in the week before Hanukkah (our December). Then John, rather than Jesus would have been conceived on or about Hanukkah. Jesus would then, by our assumption, have been conceived approximately six months later, in the month of Sivan, shortly after Pentecost. Jesus would then be born nine months later, in the month of Adar. That doesnít make as neat a solution, because the holiday in Adar is the rabbinic holiday of Purim. (But there is no reason to assume Jesus was born on a holiday.)
Now for the next complication. The Hebrew calendar does not correspond directly with the Gregorian calendar. If we figure that Jesus was born on Purim, or even on Tabernacles, we are using the Hebrew calendar. Since that calendar actually adds a month on a regular basis, we still could not determine a specific date on the Gregorian calendar to celebrate his birthday. Tabernacles may start in September or October, and Purim may come sometime in February, March, or April.
Now, somebody may be asking, ďWhat difference does it make?Ē That is a very good question. We like to celebrate birthdays, but the point of Jesus being born is only as a prelude to the date of his death. It is significant in that the son of God appears as a human. Nevertheless, we memorialize his death and resurrection every week in the Lordís Supper. It seems a triviality, in comparison, to argue once a year about when Jesus was born.