I believe that things can be accomplished that are utterly and completely impossible without the intervention of a divine Creator. We call them miracles. They don’t need historical or scientific defense. And they don’t have to make philosophical or logical sense either. If God is God, and He is, then miraculous things are possible with Him.
Hundreds of years before Jesus was born, the prophet Isaiah foretold his coming.
Therefore the Lord himself will give you a sign: The virgin will conceive and give birth to a son, and will call him Immanuel.
– Isaiah 7:14 NIV
The virgin birth would become a sign to Israel, the ultimate confirmation that full and final deliverance would indeed occur for the nation. But the virgin birth is a sign of much more than this.
Jesus’ virgin birth was a sign that God could indeed act in the affairs of mankind to bring about supernatural events. That He could overcome the laws of nature, which He Himself authored, to cause miracles to occur. And ultimately, the virgin birth is a sign to us that God alone is powerful to act on our behalf in salvation. The gift of salvation is not something we could ever obtain in our own merit or power. We are absolutely dependent on a sovereign God.
If Jesus could be born to a virgin Mary, he can certainly save any of us who trusts in him.