"The reason the Son of God appeared was to destroy the works of the devil." - I John 3:8
Why the Incarnation? Why the Word become flesh? Why Christmas? John tells us why the Son of God appeared: to destroy the works of the devil. The invading Messiah King promised of the house of David came at Christmas and live as our righteousness for Triumphal Entry, Good Friday, Easter, and Ascension to destroy the works of the devil.
Jesus destroys the works of the devil by taking away our sin (I John 3:5). This is why John writes this letter, that the readers, "little children," do not sin. John delights knowing the children walk in the truth (III John 4). Jesus took the sins of those who believe in Him to the cross. He is our righteousness, making propitiation by His blood (I John 2:2, 4:10). Jesus destroys the works of the devil that we, as little children, would not sin or make a practice of sinning. And, when we do sin, Jesus advocates for us against the devil's work as accuser.
Jesus destroys the works of the devil by forgiveness as well as the power of sin for us. Why Christmas? The Son of God became human like us "that through death He might destroy the one who has the power of death, that is, the devil, and deliver all those who through fear of death were subject to lifelong slavery" (Hebrews 2:14-15). The Son of God came "to save us all from Satan's power when we were gone astray."
As the angel told the Bethlehem shepherds, "Fear not, for behold, I bring you good news of great joy that will be for all the people. For unto you is born this day in the city of David a Savior, who is Christ the Lord." A Savior! This good news of great joy that Christ the Lord and Savior has come to destroy the works of the devil lent the shepherds to return to their fields "glorifying and praising God for all they had heard and seen" (Luke 2:20).
Dear reader, Jesus came to destroy the works of the devil. This is good news of great joy! Rest your sinful heart upon Christ who is the righteous King. The power of the devil's works in the hearts of the sons of disobedience is no match for Christ who takes those dead in sins and trespasses into new life (Ephesians 2:1-2). Born in the city of David a Savior, who is Christ the Lord. Glory to God in the highest, and on earth peace among those with whom He is pleased!