The gospel rests on three giant pillars: Jesus’ virgin birth, atoning death, and bodily resurrection. The Easter season celebrates Jesus’ death and resurrection. Christmas focuses on the virgin birth. You can’t call yourself a Christian if you don’t believe in the virgin birth. 
As I was watching the movie, “The Nativity,” I was reminded that Mary wasn’t as startled by the angel’s appearance as she was by the message. “How will this be,” Mary asked the angel, “since I am a virgin?” (Luke 1:34)
Isn’t it equally interesting that the Lord chose a doctor to write about it? As a physician, Luke’s training would have prejudiced him against the whole idea of a virgin birth. Yet, facing the evidence of his own training, he was so completely convinced of its truth that the he wrote the longest, most detailed, and most beautiful account of this marvelous event.
Well we all know that Gabriel ultimately convinced Mary to get beyond what her earthly mind tells her can’t happen. “For nothing is impossible with God,” he told her. (Luke 1:37)
What we see at work in the life of Mary is a test of faith. The Bible tells us that “faith is the substance of things hoped for, the evidence of things not seen”. (Hebrews 11:1) The world told Mary that it couldn’t be, but God told her to believe otherwise. Think about it. Mary’s decision to submit to God’s will could have meant shame before her friends and family, not to mention the possible loss of a husband to whom she was engaged. She could have been stoned to death for becoming pregnant during her engagement. What a leap of faith!
God showed Mary, and the rest of us, too, what happens when we’re willing to forsake the world’s logic to accept His infinite promise that nothing is impossible when He’s in the middle of it. Mary’s greatest shame became her greatest glory.
So you see the Christmas story also demonstrates what can happen when we allow our faith to reach beyond what we understand. It’s that very same faith today that brings stories of healings our way, delivers alcoholics, gamblers and drug addicts from destructive addictions, restores broken relationships, comforts a grieving spouse, and reminds us all that hope for the Christian is never lost.