Amazingly, the New Testament does not start with the birth of Jesus; it starts with the birth of John the Baptist. That may be surprising; however, it is significant to us in understanding the birth of Jesus.
We read Luke 1:5:
“There was in the days of Herod, the king of Judea, a certain priest named Zacharias, of the division of Abijah.”
Thus begins Luke’s Gospel account. Zacharias was a priest who served in the Temple in Jerusalem according to the division of Abijah. Most Bible readers read over the words, “division of Abijah,” without ever asking: What does it mean? What is the division of Abijah and what does this have to do with Jesus? Take a deep breath. Settle yourself. This is going to be exciting!
Way back in the Old Testament, King David of Israel set up a schedule as to when priests were to serve at the tabernacle (later the Temple). We read in 1 Chronicles 24:3:
“Then David with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, divided [the priests] according to the schedule of their service.” In verse 10 we read: “. . .the seventh to Hakkoz, the eighth to Abijah.”
So, the division of Abijah was the eighth division.
To put it very simply: each division of priests was to serve for one week according to its division (or “course” as it is rendered in the King James Version), except for the time of the festivals when all priests were to serve, for the obvious reason that great multitudes would have come to Jerusalem for the feasts so they needed all the priests on hand.
From this information we can readily determine when Zacharias was doing service in the Temple. The schedule for the priests to serve started at the beginning of the year according to the Hebrew calendar: the new moon of March/April. Each division served for a week. Eight weeks into the year brings us to May/June except that, if you were familiar with the festivals (called Jewish festivals today), you would know that the first festival is celebrated in the first month (see Leviticus 23:5-8), when all priests served. That would mean that Zacharias was actually in the Temple in the ninth week of the year.
What happened to Zacharias when he served in the Temple? Please read Luke 1:5-25 where you will find that Gabriel, the angel of God, appeared to Zacharias and told him that he and his wife, Elizabeth, would have a child, a boy, whom they were to call John. This was the one who became John the Baptist, a very important person in the New Testament.
One would assume that Zacharias would have gone home to his wife at the end of the ninth week; however, that was the week of the Feast of Weeks (see Leviticus 23:15-16), also called the Feast of Firstfruits (or Pentecost in the New Testament) when all priests were again to serve in the Temple. So Zacharias would have gone home after Pentecost, mid to late June. That is when John would have been conceived. Why is this important and what has it got to do with Jesus? Notice Luke 1:26: “Now in the sixth month . . .”
The sixth month of what? What was it talking about? It was talking about Elizabeth getting pregnant with John. It was talking about the sixth month of Elizabeth’s pregnancy. Continue Luke 1:26-33:
“Now in the sixth month the angel Gabriel was sent by God to a city of Galilee named Nazareth, to a virgin betrothed to a man whose name was Joseph, of the house of David. The virgin’s name was Mary. And having come in, the angel said to her, ‘Rejoice, highly favored one, the Lord is with you; blessed are you among women!’ But when she saw him, she was troubled at his saying, and considered what manner of greeting this was. Then the angel said to her, “Do not be afraid, Mary, for you have found favor with God. And behold, you will conceive in your womb and bring forth a Son, and shall call His name Jesus. He will be great, and will be called the Son of the Highest; and the Lord God will give Him the throne of His father David. And He will reign over the house of Jacob forever, and of His kingdom there will be no end.”
What can we conclude from all this? The simple conclusion is that John the Baptist was six months older that Jesus, and, yes, by this we can find out when Jesus was born!
If John was conceived late June, when was he born? Nine months later: March/April the next year. When was Jesus born? Easy: six months later: September/October. Q.E.D.—as we used to write at the end mathematical theorems in high school, from the Latin: quod erat demonstrandum— or quite easily done! Yes, that is how easily we can prove when Jesus was born. From the clear information given to us in the Gospel according to Luke, Jesus was born September/October. He certainly was not born in December, the middle of winter, or on the pagan Saturnalia, which was celebrated December 25 on the Roman calendar.