The Bible does reveal the very likely birth date for Jesus Christ, but the date is not December 25th. December 25th was selected by the church as a day to observe His birth; and for that purpose it is fine to do. But Christ's actual birth took place in 7 BC, during the Hebrew 7th month. The Hebrew 7th month takes place about our September/October. It can be shown from the Bible that Jesus Christ was born about October 1, or October 2, in 7 BC.
It's a little complicated, but here is how we can determine the actual birth date for Jesus Christ: first we must determine the birth time for John the Baptist, then we will be able to know when Christ was born.
Luke 1:5 There was in the days of Herod, the king of Judaea, a certain priest named
Zacharias, of the course of Abia:
Zacharias, the father of John the Baptist, was of the course of Abia. The priests and Levites performed ministry in the temple according to course. We read of the various courses in 1 Chronicles 24:
1 Chronicles 24:1 Now these are the divisions of the sons of Aaron. The sons of Aaron; Nadab, and Abihu, Eleazar, and Ithamar.
2 But Nadab and Abihu died before their father, and had no children: therefore Eleazar and Ithamar executed the priest's office.
3 And David distributed them, both Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their offices in their service.
These divisions (or courses) were divided up 2 per month.
1 Chronicles 24:7 Now the first lot came forth to Jehoiarib, the second to Jedaiah,
8 The third to Harim, the fourth to Seorim,
9 The fifth to Malchijah, the sixth to Mijamin,
10 The seventh to Hakkoz, the eighth to Abijah,
11 The ninth to Jeshua, the tenth to Shecaniah,
12 The eleventh to Eliashib, the twelfth to Jakim,
13 The thirteenth to Huppah, the fourteenth to Jeshebeab,
14 The fifteenth to Bilgah, the sixteenth to Immer,
15 The seventeenth to Hezir, the eighteenth to Aphses,
16 The nineteenth to Pethahiah, the twentieth to Jehezekel,
17 The one and twentieth to Jachin, the two and twentieth to Gamul,
18 The three and twentieth to Delaiah, the four and twentieth to Maaziah.
19 These were the orderings of them in their service to come into the house of the LORD, according to their manner, under Aaron their father, as the LORD God of Israel had commanded him.
Please take note, that the 8th lot was for "Abijah", or Abiah as he is called in Luke's gospel. The 7th and 8th lot would fall in the Hebrew 4th month (2 lots per month, 24 total lots divided by 12 equal 2 per month).
This means that we know that Zacharias, due to his course being of Abiah, was ministering in the temple during the Hebrew 4th month. It was at this time the Angel of God appeared to him and told him that his wife Elisabeth would have a son. Zacharias would have been greatly motivated to get home to his wife as soon as possible after finishing his course:
Luke 1:23 And it came to pass, that, as soon as the days of his ministration were accomplished, he departed to his own house.
24 And after those days his wife Elisabeth conceived, and hid herself five months, saying,
We read in the above verses that he did depart to his own house as soon as his period of ministration were accomplished. His ministry of the 8th course of Abijah was finished at the point of the end of the Hebrew 4th month. Zarcharias went immediately home and certainly would have been intimate with his wife Elisabeth. Therefore we can understand that John the Baptist was conceived at the end of the 4th month, probably at the very beginning of the Hebrew 5th month.
How does this relate to the birth of Jesus Christ? Well, Mary, the woman God chose to give birth to Christ as a virgin was related to Elisabeth. We find that God visited Mary and told her of the child she would have. And then Mary visited her cousin Elisabeth:
Luke 1:30 And the angel said unto her, Fear not, Mary: for thou hast found favour with God.
31 And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS.
32 He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David:
33 And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end.
34 Then said Mary unto the angel, How shall this be, seeing I know not a man?
35 And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God.
36 And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren.
37 For with God nothing shall be impossible.
38 And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.
39 And Mary arose in those days, and went into the hill country with haste, into a city of Juda;
40 And entered into the house of Zacharias, and saluted Elisabeth.
41 And it came to pass, that, when Elisabeth heard the salutation of Mary, the babe leaped in her womb; and Elisabeth was filled with the Holy Ghost:
42 And she spake out with a loud voice, and said, Blessed art thou among women, and blessed is the fruit of thy womb.
Now we have sufficient information to piece together the birth date for Jesus.
Elisabeth, John Baptist's mother became pregnant with John early in the Hebrew 5th month (of 8 BC). 6 months later, either the end of the Hebrew 10th month, or at the very beginning of the Hebrew 11th month, Mary visited Elisabeth who was 6 months pregnant. Christ had just been conceived by the Holy Ghost in her womb. Therefore we know that Jesus Christ was early in the womb of the virgin Mary at the end of the Hebrew 10th month, or very early of the Hebrew 11th month in 8 BC.
9 months later (as the Bible gives no indication Christ's birth was anything but a normal birth) Jesus was born. 9 months from the Hebrew 10th month would be as follows:
(months are Hebrew calendar months)
10 to 11th month-- Jesus 1 month old in womb
11 to 12th month---Jesus 2 months old in womb 12 to 1st month---Jesus 3 months old in womb 1st to 2nd month---Jesus 4 months old in womb 2nd to 3rd month---Jesus 5 months old in womb 3rd to 4th month---Jesus 6 months old in womb 4th to 5th month---Jesus 7 months old in womb 5th to 6th month---Jesus 8 months old in womb 6th to 7th month---Jesus 9 months old in womb
Therefore Jesus Christ was born during the Hebrew 7th month, which is our October, in the year 7 BC.