Do Protestants Have the "Fullness of the Faith"?
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Do Protestants Have the "Fullness of the Faith"?

The Who, When, & Why of Christmas

Posted December 23, 2021

Behold, the virgin shall conceive and bear a son, and they shall call his name Immanuel!

It’s that time of year when Christians throughout the world celebrate what God has accomplished in history. During this time in particular, we celebrate the incarnation. For those unfamiliar with this event, and for those whose understanding could use a little deepening, here is the who, when, and why of what took place:


During Christmas we celebrate the birth of God. That might sound odd (how does God have a birthday?), but it’s what the church throughout history has confessed. The Virgin Mary did not give birth to a mere man, who was filled with God’s Spirit or empowered by God uniquely, but to God the Son.

This is why the church has called Mary Theotokos, which means God-Bearer. It’s a title meant to highlight that God himself took flesh in the womb of a virgin and was born. At times, the church fathers articulated this by speaking of God the Son being born twice. He who was eternally begotten of the Father (i.e. never had a beginning) was born in time by assuming humanity through the womb of the Virgin Mary. The baby who was born is the same one who upholds the entire universe by his powerful word!


The incarnation signals a very important shift in world history. The apostle Paul wrote,

But when the fullness of time had come, God sent forth his Son, born of a woman, born under the law. (Gal. 4:4)

The Eternal Word of God was born of the Virgin Mary when the fullness of time had arrived. More than saying “Jesus came at the perfect time,” this is telling us that the “when” of the incarnation signals a shift from one era to another.

The “old age” of sin and death is coming to an end, because the light of a new age has dawned with Christmas, since “the darkness is passing away and the true light is already shining” (1 John 2:8). Jesus is the “Light of Light” whose incarnation breaks through the darkness of the old age and ushers in a new one.


Why was God born when the fullness of time had come? Christians confess why in the Nicene Creed. We believe in one Lord Jesus Christ “who for us and for our salvation, came down from heaven.” This is no doubt the reason why we celebrate. God could have come to judge us for our sins, but instead he came to save us from them! God, the Eternal Word, was born for me and you. The early church father Gregory of Nyssa wrote,

Here is the reason for God’s presence among men. Our nature was sick and needed a doctor. Man had fallen and needed someone to raise him up. He who had lost life needed someone to restore it. He who had ceased to participate in the good needed someone to bring him back to it. He who was shut up in darkness needed the presence of light. The prisoner was looking for someone to ransom him, the captive for someone to take his part. He who was under the yoke of slavery was looking for someone to set him free. (The Great Catechism, sec.15)

We were the fallen, the prisoners, the captives, the slaves. Instead of leaving us destitute, God came to us, being born to save us: “‘Behold, the virgin shall conceive and bear a son, and they shall call his name Immanuel’ (which means, God with us)” (Matt. 1:23).

It is for these reasons that Christians throughout the world celebrate during this time of year. God the Word was born when the fullness of time had come, in order to save us! O Come, let us adore Him! Let choirs of angels sing! Let the whole world rejoice because Christ was born!

Photo of Adriel Sanchez
Adriel Sanchez

Adriel Sanchez is pastor of North Park Presbyterian Church, a congregation in the Presbyterian Church in America (PCA). In addition to his pastoral responsibilities, he also serves the broader church as a host on the Core Christianity radio program, a live, daily call-in talk show where he answers listeners' questions about the Bible and the Christian faith. He and his wife Ysabel live in San Diego with their five children.