The term "incarnation" means "to become flesh."
The incarnation is that event where the second person of the Trinity – God the Father; God the Son; and God the Holy
Spirit, became human.
The term "incarnation" is not found in the New Testament, but the concept is clearly defined in the following scripture
John 1:1-3 "In the beginning was the Word, and the Word was with God, and the Word was God. 2 He was with God in the beginning.3 Through Him all things were made; without Him nothing was made that has been made."
John 1:14 "And the WORD became flesh and dwelt among us..."
When the Word became flesh, He dwelt in the womb of Mary and was born as Lord Jesus.
Lord Jesus is the incarnation of God and God in flesh.
Col. 2:9 "for in Him dwells all the fullness of deity in bodily form."
6 Who (Christ), being in very nature God, did not consider equality with God something to be used to HIS own advantage;
7 rather, HE made himself nothing by taking the very nature of a servant, being made in human likeness.
8 And being found in appearance as a man, HE humbled Himself by becoming obedient to death even death on a cross!
1 Tim. 3:16
Beyond all question, the mystery from which true godliness springs is great: He appeared in the flesh, was vindicated by the
Spirit, was seen by angels, was preached among the nations, was believed on in the world, was taken up in glory.
I like the way Pastor Chuck Swindoll puts it.
Incarnation was in the bigger plan of God before anything was created by God.
It is mind boggling, beyond human comprehension,and an unresolved mystery
15 The Son is the image of the invisible God, the firstborn over all creation.
16 For in HIM (Christ) all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through HIM (Jesus Christ) and or HIM.
17 He is before all things, and in HIM all things hold together
So God created the universe, Galaxies, the Solar system and Planet Earth for His Incarnation.
The purpose of creation was for Lord Jesus to come into this world as a human.
And the purpose of His Incarnation was to redeem the sinful humanity from sin so they can have an eternal relationship with God.
The Bible says sin came into this world thru one man Adam.
Since then everybody born to a woman is a sinner by birth and carry in his/her DNA.
Sin cannot be removed by any rituals, practices, good works, pilgrimages, sacrifices, vows or religious living.
Sin is cleansed only by the blood of Lord Jesus Christ who died on the cross for us all.
Only sinless man, Lord Jesus, can pay that price for sin required by God.
On Christmas Day, God became a man so that He can die and pay the price for human sin once for all so that you and I can live eternally after our death.
That is why we celebrate with great joy that a Savior is born some 2000 years ago.