How does the virgin birth affect Jesus’ divinity?

TL;DR:

The virgin birth didn’t make Jesus divine—He was already eternally God. The virgin birth allowed Jesus to be both truly human and the perfect Savior for our sins.

The virgin conception and birth refer to Jesus’ incarnation, the point when the Son of God added on humanity. However, the Son of God was eternally divine (John 1:1; John 8:58; Hebrews 1:3). So, His divinity was not added nor did it begin at conception. Instead, He always was divine, with humanity added later.

Being born of a virgin “affected” His divinity in that it safeguarded the integrity of His incarnation and His sinlessness. As fully God, the Son was perfectly holy. When Adam sinned, God judged the world with death and corruption (Genesis 3:17–19), and all humans are conceived under sin (Psalm 51:5). Thus, in Adam all are sinners (Romans 5:12, 19) and by nature children of wrath (Ephesians 2:3). Had the Son entered humanity through ordinary conception, He would have entered Adam’s fallen condition.

Instead, the Holy Spirit caused Mary, a virgin, to conceive (Matthew 1:18–23; Luke 1:34–35). Jesus was, therefore, called "holy" from conception (Luke 1:35). The virgin birth safeguarded His true humanity while ensuring that His human nature, like His divine nature, was without sin (Hebrews 4:15; 2 Corinthians 5:21).

from the old testament

When Adam sinned, God judged all of humanity with death (Genesis 3:17–19). The theological implication of this is our corrupted, sinful nature, meaning that we are conceived and born sinful (Psalm 51:5).
However, when God cursed humanity, He promised that there would be a redeemer who was specifically an offspring (or “seed”) from the woman who would crush the serpent (Genesis 3:15). This was an unusual statement since normally children are referred to as the descendants of their father (i.e., Genesis 5).
Later, it was said that a “virgin shall conceive and bear a son, and shall call his name Immanuel” (Isaiah 7:14). The word “Immanuel” meant “God with us.” That child was also to be known as “Mighty God” and “Everlasting Father” (Isaiah 9:6). Thus, the Old Testament anticipated a Messiah who would come from a virgin woman and be both human and God.

from the new testament

Matthew opens by showing that Jesus is fully human, being in the Davidic line (Matthew 1:1–17) yet also born of a virgin (Matthew 1:23).
John explained that before He came to earth, “the Word,” (another name for Jesus), “was with God, and the Word was God” (John 1:1). That is, the Son of God was both eternal and fully God. Jesus also claimed to be God (John 8:58-59, 10:30, 14:9b). All this reinforces that the virgin birth did not make Him divine; it ensured He was sinless in His humanity, just like He was eternally holy in His divinity.
All men and women are born under the curse given to Adam (Romans 5:12, 19). However, Jesus was conceived by the Holy Spirit (Matthew 1:18–23), who caused a virgin, Mary, to be pregnant with Him. Just as in Genesis 3:15, Jesus was born of a human mother but not a human father. As the angel Gabriel told Mary, the result was “the child to be born will be called holy—the Son of God” (Luke 1:35c).
Jesus’ virgin birth did not affect His divinity and ensured that He would also be holy in His humanity. Becaues of this, He is a Savior who sympathizes with us in our humanity but “one who in every respect has been tempted as we are, yet without sin” (Hebrews 4:15).

implications for today

Someone picking up the tab can make your day. We might mention it to others in our sphere and send a text to thank (again) the one who paid. Jesus did much more, though, and many don't acknowledge it: He took on our sin debt.

No one would could have done that because no one else is sinless. This is why the virgin birth is one of the core doctrines that cannot be denied. It is more than a “fun fact” of Christianity but the very foundation of how Jesus can be truly human yet also truly sinless. Unlike us, Jesus did not inherit Adam’s guilt and corruption like the rest of humanity.

Shouldn't others know the debt Jesus paid for them so they can put their faith in Him and receive eternal life? Of course—we shouldn't be like the man in Jesus' parable who buried his master's money rather than multiplying it (Matthew 25:14-30). We must tell others of the only hope for humanity: Jesus.

understand

Jesus was eternally divine before His conception and did not become God at the virgin birth.
The virgin birth safeguarded the integrity of the incarnation by preventing Jesus from entering Adam’s fallen condition.
Through the Spirit’s work in Mary's conception, Jesus was fully human and fully sinless, qualifying Him to be our Savior.

reflect

Why is it important that the Son of God did not begin to exist at His conception but has always been God?
How does knowing that Jesus took on real humanity without sin strengthen your confidence in His saving work?
When talking about Jesus to others, how do you present the virgin birth?

engage

How does denying the virgin birth affect the doctrines of original sin and Christ’s sinlessness?
In what ways does the promise of Genesis 3:15 connect to the New Testament accounts of Jesus’ conception?
How does the union of full divinity and full humanity in one person guard against common Christological errors?