The Christmas holidays remind me of that time when God "knocked on the door" of his only Son to give him a unique mission to come to earth. The mission would begin in a common stable, in a small country under the domination of the Roman Empire. There would be no great national celebration of the birth of King Jesus. In fact, for the first 30 of his 33 years on earth, people in the marketplace weren't even aware they were rubbing shoulders with the Creator of the universe!
Jesus didn't go on a campaign trail to secure this mission. He didn't raise his hand wildly, saying "Pick me, pick me!" He knew from the very beginning that his mission would be coming to earth as a baby boy, born to a virgin. During his time on earth there would be humiliation, unbelief, opposition, and finally, crucifixion. But he came. He came because his Father opened the door of opportunity for him to save the world. "For God did not send his Son into the world to condemn the world, but in order that the world might be saved through him." (John 3:17).
The incarnation—God the Son taking on humanity—would not be a lucrative career move for Jesus. It was not for something bigger and better. It actually was a huge step down to the role of a humble man. In fact, the Bible says that though he was in the form of God, he made himself nothing, "taking the form of a servant, being born in the likeness of men" (Philippians 2:6-7).
When Jesus Christ opened the door to receive his Father's plan, he literally changed the course of history. Over time, his coming would be used to separate history in two—BC ("Before Christ") and AD ("Anno domini"—in the year of our Lord). That's because of the amazing nature of his mission. He didn't come "to be served but to serve, and to give his life as a ransom for many" (Mark 10:45), making it possible for sinner like us to be forgiven of our sins and to receive eternal life from God!
Knowing that "the wages of sin is death" (Romans 6:23), Jesus Christ completed his mission by taking the punishment for our sins with his own life. God "did not spare his own Son but gave him up for us all" (Romans 8:32). Jesus "bore our sins in his body on the tree....the righteous for the unrighteous, that he might bring us to God" (1 Peter 2:24; 3:18). Once justice had been done, God could forgive us so that "whoever believes in him should not perish but have eternal life" (John 3:16).
From his own testimony, Jesus declared his mission by saying, "The spirit of the Lord GOD is upon me....He has sent me to bind up the brokenhearted, to proclaim liberty to the captives" (Isaiah 61:1). Jesus's birth, life, death, resurrection, and return to heaven completed his mission (1 Corinthians 15:1-8). Since then he has set free countless prisoners of sin who otherwise would face eternal judgment. He has brought spiritual sight to men and women who were blindly headed for eternal destruction. His "mission accomplished" has released millions from the oppression of sin and its consequences.
Just as God knocked on the door of Christ's heart, now Christ stands at the door and knocks on every human heart. His arms are loaded with packages that he has carefully prepared to deliver to anyone who opens the door. Christ says, "I stand at the door and knock. If anyone hears my voice and opens the door, I will come in" (Revelation 3:20).