But when the set time had fully come, God sent his Son, born of a woman, born under the law, to redeem those under the law, that we might receive adoption to sonship.
~ Galatians 4: 4-5 ~
These words of Paul in his letter to the Galatians sum up both Christmas and Easter.
The fullness of time refers to God's perspective. In the Old Testament particularly in the book of Daniel, the time of His first coming is prophesied, specifically the Triumphal Entry into Jerusalem. In Galatians His incarnation is evident in the sense that He is the Son of God sent forth, meaning that he pre-existed his human nature, as the eternal Son of God; he became human through being born of Mary.
He came to redeem lost humans by being our substitute upon the cross for our sins. The Judge of the universe came down from His throne and died in our place and rose again the third day. We have eternal life through receiving Jesus Christ into our lives as our Lord and Saviour.
That is good news!