Christ was born in human form and named Jesus because He would save His people from their sins, which is what the angel said to Joseph in Matthew 1. This is why the incarnation of God the Son was so necessary for God’s redemption of man through His Messiah. Christ had to be born of a woman so that He would have a human body in order to die as our sin sacrifice; Christ had to be born as a man in order to be tempted and know the experience of mankind; Christ had to be God so that He could be sinless and die as our substitute paying our debt of sin; Christ had to be human so He would have blood to shed because sin is only remitted by the shedding of blood as in the original sacrifice for sin in Genesis 3. However, that blood had to be sinless so that it could cleanse our sins away; therefore, Christ had to be Holy God as well as human flesh. God is the law giver and not under the law, so God had to be born under the law so He could redeem mankind who is under the curse of the law. So, when Christ came to earth, He was born of Mary who was a virgin and not merely a young maiden. The conception of Christ in the womb of Mary was a miraculous event far more than it was a biological one. It was biological in the formation of the flesh and bone and body developing inside of her, but the conception itself was far beyond anything natural and normal in the biological event of conception. It was miraculous in the fact that God accomplished it in her but not through a man. It was miraculous in that it was not a sexual encounter at all. The virgin conception of Christ was an event that was accomplished by the will of God, not the will of man in fulfillment of the Word of God. Since there was no disruption of her virgin state in the conception of Christ and of the birth of Christ, when Joseph finally consummated his union with his wife after the birth of Christ, she was still his virgin bride, which was miraculous as well. When Christ was born of Mary, she called His name Jesus because He came to save His people from their sins by dying for their sins as their sacrifice on the cross.