Since Christmas is a Christian holiday it ought to be defined by the same rulebook that controls the entirety of Christianity, the Holy Bible.
Although not demanded, suggested, or even mentioned in the Bible, the celebration of Christmas has been a part of Christian tradition for much of the time since his birth.
There is no substantial argument about who is rightly the focus of the celebration.
In the time of the Prophets in Old Testament days it was revealed that in the distant future an unmarried maiden, aka a virgin, would conceive and bear a son. The message from God to the Prophet Isaiah stipulated that the boy was to be named Immanuel, which means “God with us”.
When the time came for these things to happen the virgin maiden was told by a visiting angel to call his name JESUS. And so it is universally accepted that Christmas is a celebration of the birth of Jesus.
Jesus carries the title “Christ”, so most recognize the name Jesus Christ.
Jesus was born to a woman who had never been with a man. She was miraculously impregnated by a direct act of God. The virgin’s boy child is the Son of God!
Jesus is both fully Man and fully God. He is one of the three personages of the one true God.
Jesus is God become Man. He became Man in order to fulfill the terms of pardon for all who accept the truth of his story. Those who reject his story as false are not pardoned and remain condemned. This is known as The Gospel of Jesus Christ. It is the good news that the sentence of death, into which all humans are born, can be pardoned, and eternal life is possible.
Jesus came to Earth to destroy the works of the Devil who delights in deceiving people and causing them to miss the pardon.
A true and proper Christmas celebration focuses on the birth of the Savior, the Messiah, Immanuel, the only Redeemer of God’s chosen people… Jesus Christ.