The real Christmas story is found in Matthew (Matt. 1:18-2:18) and in Luke ( Luke 1:26-56, 2:1-40). However, Isaiah should never be ignored:
Behold, the virgin shall conceive and bear a son, and shall call his name Immanuel. (Isaiah 7:14)
For to us a child is born,
to us a son is given;
and the government shall be upon his shoulder,
and his name shall be called
Wonderful Counselor, Mighty God,
Everlasting Father, Prince of Peace. (Isaiah 9:6)
Matthew gives us the story largely from the perspective of Joseph, including the dreams that he had and his family genealogy. In this gospel the ‘Kingship’ of Jesus is the major topic. Starting with the Davidic Kingly genealogy through Joseph and the coming of the Magi (Wisemen) who are looking for the new king. Also King Herod’s reaction is in Matthew.
The events in Luke are given to us from Mary’s view. The angel Gabriel appears to Mary and announces the coming of the child. Mary’s genealogy is also given in Luke (Luke 3:23-38), she was also a descendant of David, but not in the ‘Kingly’ line. Chapter 2 begins with the Christmas story that everyone is familiar with:
1 In those days a decree went out from Caesar Augustus that all the world should be registered. 2 This was the first registration when Quirinius was governor of Syria. 3 And all went to be registered, each to his own town. 4 And Joseph also went up from Galilee, from the town of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and lineage of David, 5 to be registered with Mary, his betrothed, who was with child. 6 And while they were there, the time came for her to give birth. 7 And she gave birth to her firstborn son and wrapped him in swaddling cloths and laid him in a manger, because there was no place for them in the inn.
8 And in the same region there were shepherds out in the field, keeping watch over their flock by night. 9 And an angel of the Lord appeared to them, and the glory of the Lord shone around them, and they were filled with fear. 10 And the angel said to them, “Fear not, for behold, I bring you good news of a great joy that will be for all the people. 11 For unto you is born this day in the city of David a Savior, who is Christ the Lord. 12 And this will be a sign for you: you will find a baby wrapped in swaddling cloths and lying in a manger.” 13 And suddenly there was with the angel a multitude of the heavenly host praising God and saying,
14 “Glory to God in the highest,
and on earth peace among those with whom he is pleased!”
However, nothing explains the real reason for the season better than John 3:16-17:
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
For God sent not his Son into the world to condemn the world; but that the world through him might be saved. -KJV