John's Gospel speaks of the humanity and divinity of Christ in different terms. John begins by highlighting the eternal divinity of Christ with these phrases.
"In the beginning was the Word, and the Word was with God, and the Word was God. He was in the beginning with God. All things came into being through Him, and apart from Him nothing came into being that has come into being (John 1:1-3)."
Then, a few verses later, John declares the humanity of Christ with this phrase.
"And the Word became flesh, and dwelt among us, and we saw His glory, glory as of the only begotten from the Father, full of grace and truth. John testified about Him and cried out, saying, 'This was He of whom I said, 'He who comes after me has a higher rank than I, for He existed before me (Jn 1:14-15).' "
Paul also declares both the humanity of Christ (Gal 4:4) and his divinity (Col 2:9). The Hebrew writer declares both the divinity of Christ (Heb 2:10) and his humanity (Heb 2:14). Why is this so important to be repeated in so many different ways in scripture? Why did he have to have a special relationship with both God and Humanity?
The special relationship that Jesus has with both God and humankind allows him to do what no one else is able to do. Not only does Jesus bring the presence of God to us, but he also enables us coming into the presence of God. Consider these examples:
"For there is one God, and one mediator also between God and men, the man Christ Jesus (1 Tim 2:5),"
"My little children, I am writing these things to you so that you may not sin. And if anyone sins, we have an Advocate with the Father, Jesus Christ the righteous (1 Jn 2:1);"
"Therefore, He had to be made like His brethren in all things, so that He might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people (Heb 2:17)."
"... Jesus has entered as a forerunner for us, having become a high priest forever according to the order of Melchizedek (Heb 6:20)."
Only Jesus could be a mediator between men and God because only Jesus was both human and divine. Jesus became an effective advocate to speak to the Father on our behalf because he has walked in our shoes. Not only does he know and understand us, he knows and understands God.
Only Jesus could be a merciful and faithful high priest because only Jesus was "made like his brethren in all things." Because Jesus is a merciful and faithful high priest, he became a "forerunner" for us by offering a way to come to God. Jesus is the way, and the means by which he became the way was through becoming human himself and making atonement for our sins.
So, the doctrine of the virgin birth is very significant. Without it, we do not have a true mediator. Thank God for our savior Jesus Christ!