You’ll often hear people say that Jesus wasn’t born on December 25th, that he was likely actually born in the Spring, and that Christmas is really just a Christianized pagan holiday.
Here’s the truth: the early Church celebrated Christmas on December 25th because that’s the day they thought Jesus was born.
They had two arguments for this date.
First, they believed that Jesus was crucified on March 25th (given when Passover normally falls), and there was a tradition that Jesus died the same day he first entered the world (his conception). Nine month later from March 25th is December 25th.
Second, and most importantly, Scripture provides strong evidence that December 25th, or a date near that, is when Jesus was born.
The Gospel of Luke tells us the angel Gabriel revealed to 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 Jewish holy day always falls in 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.
Now just do the math: 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. And if Mary conceived Jesus in late March, that places his birth in late December.
So it’s very possible the early Church got it right, and December 25th really is Jesus’ birthday!
Source: catholicpop.com