Christians in the early Church thought December 25th was the actual day of Christ’s birth, and they had good reasons for thinking so.
We celebrate the birth of Christ on December 25th, but that’s just ceremonial, right? Actually, December 25th might be the right date.
Though Scripture doesn’t tell us the exact date of Christ’s birth, there are two ways to get to December 25th:
1) The Date of Christ’s Death
This one might seem counterintuitive, but early Christians were very interested in historical symmetry and numbers and there was a tradition in the early Church that Jesus entered the world on the same day that he left the world; in other words, that he was conceived on the same day that he died. Since Christian believed he died on March 25th, it was believed that Jesus was conceived on March 25th. That of course places his birth on December 25th.
2) The Conception of John the Baptist
This second method might be more palpable to modern people since it simply follows the information provided in the historical record of Jesus’ birth provided in the Scriptures.
In the first chapter of Luke, we read that the angel Gabriel told Zechariah that his wife Elizabeth would conceive John the Baptist while Zechariah was performing his priestly duties on the Day of Atonement, also known as Yom Kippur. That feast always falls in either late September or early October.
Luke also tells us that, after Gabriel announced to Mary that she would conceive Jesus, she went in haste to visit Elizabeth, and that Elizabeth was in the sixth month of her pregnancy. If Elizabeth conceived in late September, and Mary visited her in her sixth month, that means Mary conceived Jesus and visited Elizabeth in late March. If Mary conceived Jesus in late March, that places his birth in late December.
So it’s very possible that the early Church got it right, and December 25th really is the actual birthday of Jesus!