Is there good reason to reject December 25 as Jesus' birthdate?
Question: Does the Bible indicate the date, or even the season, of Christ's birth?
Answer: One key to the accurate dating of Jesus Christ's birth is contained in a biblical statement about Zacharias, the father of John the Baptist. In Luke, we are told that John's father was "of the division of Abijah" (Luke 1:5). This brief mention has great significance.
We learn from Luke that Mary, the mother of Jesus, went to visit her cousin Elizabeth right after Jesus' conception. Elizabeth was six months pregnant at the time (vv. 36-41). Thus, John the Baptist was about six months older than Jesus. So if we can determine when John was born, figuring out the approximate date of Christ's birth is a simple matter. This is where "the course of Abijah" becomes important.
About 1,000 years earlier, in the days of King David, the number of priests in Israel had grown considerably. David, therefore, divided them into 24 divisions or "courses" to rotate their service in the temple (1 Chronicles 24; cf. 23:6; 28:13). The Jewish historian Flavius Josephus wrote in the first century ad that the aforementioned partition has remained "to this day" (Antiquities of the Jews, book 7, chapter 14, section 7).
Jewish historical records show that all of the Temple priests served in Jerusalem during the three annual Festival seasons—Passover, Pentecost and Tabernacles (cf. Leviticus 23; Deuteronomy 16). Throughout the rest of the year, however, they took turns, with each course serving one week in rotating order. Their rotation began on the first Sabbath of Nisan (or Abib)—the first month on the Hebrew calendar—with each course serving from Sabbath to Sabbath.
Because all of the courses served during the week of Passover, that meant the course of Abijah—eighth in rotation (cf. 1 Chronicles 24:10)—would have come on duty at the beginning of the ninth week. And when this rotation was over, the week of Pentecost would have begun—so the course of Abijah would have remained for the tenth week as well. Luke 1 informs us that John was conceived right after his father returned home from serving at the temple (vv. 23-24). This was during the last half of Sivan, the third month of the Jewish calendar. Thus, his birth nine months or so later would have been in the spring of the next year. And since Jesus was born six months or so after John, He would have been born during the following autumn.
Such a conclusion is corroborated by two other details Luke gives us about the events surrounding Christ's birth. Luke describes that the shepherds were in the field, keeping watch over their flocks by night (Luke 2:8). Shortly after the fall harvest and the Feast of Tabernacles, in October, Judea's rainy season would have begun. By November—as the weather began to turn colder—the flocks would have been brought in for the winter. By December they would no longer have been in the fields at night with shepherds watching over them.
Another detail Luke provides is that Joseph and Mary had gone to Bethlehem at the time of a census enrollment for taxation (Luke 2:1-4). Normally such enrollments were set for right after harvest—which, again, would coincide with a fall date. This shows that, contrary to modern religious ideas, Jesus Christ was not born in the winter, but during the autumn, even though the precise day is not known.
Although it is helpful to know the general season of Christ's birth, we do not find early Christians regarding birthdays, Christ's or any other, as significant. Even as late as 245ad, the noted scholar Origen "repudiated as sinful the very idea of keeping the birthday of Christ" (Encyclopaedia Britannica, 11th edition). It is also important to note that Jesus Christ did not mark the anniversary of His birth, or make reference to it in any such fashion, nor did any of the Apostles so much as even mention Christ's birth date or their own.