Why does it matter that Jesus is God in the flesh?

from the old testament

• The Old Testament emphasizes the need for a perfect or unblemished sacrifice to atone for sins (Leviticus 4:32; 22:20–21; Exodus 12:5). These passages establish the principle that sacrifices offered to God, particularly for the atonement of sin, had to be without blemish, symbolizing the need for purity and perfection in the sacrifice that covers sin.
• God promised to send a Messiah who would bring healing, forgiveness, and restoration to a world broken by sin (Genesis 3:15; Isaiah 53:5; Jeremiah 31:31–34).
• The Bible identifies the Messiah as not only a human figure, but also as divine—God Himself come in the flesh to redeem humanity—though the revelation of this truth was cumulative (Isaiah 9:6; Micah 5:2).

from the new testament

• People have questioned Jesus’s identity since before He was born. When Mary was pregnant, Joseph, Mary's fiancé, planned to leave her until he learned from an angel that Jesus was the Son of God (Matthew 1:18–25; Luke 1:26–38).
• As a traveling rabbi, Jesus asked His disciples "Who do people say the Son of Man is?" Many answers were given. Then Jesus asked, "But who do you say that I am?" When Peter answered, "You are the Christ (Messiah), the Son of the Living God," Jesus affirmed that answer (Matthew 16:13–17; Mark 8:27–29).
• Later, Jesus equated Himself with God when He answered Philip's request for Him to reveal the Father (God). "Whoever has seen me has seen the Father. How can you say, 'Show us the Father'? Do you not believe that I am in the Father and the Father is in me? The words that I say to you I do not speak on my own authority, but the Father who dwells in me does his works. Believe me that I am in the Father and the Father is in me, or else believe on account of the works themselves" (John 14:9–11).
• John 1:1–14 identifies Jesus as God.
• Philippians 2:6–7 identifies Jesus as equating to God.
• Colossians 2:9 says that Jesus was fully divine.
• Other Scriptures that speak of Jesus's divinity include Matthew 1:23; 2:11; 14:32–33; John 8:58–59; 10:30–33; 20:27–29; and more.
• Hebrews 10:12–14 says, "When Christ had offered for all time a single sacrifice for sins, he sat down at the right hand of God, waiting from that time until his enemies should be made a footstool for his feet. For by a single offering he has perfected for all time those who are being sanctified." Nobody but God could fulfill the requirements of covering the whole world for their sins (Matthew 26:28).
• Jesus was fully God and fully human. He is the God-Man, not just God appearing to be human (Romans 5:18–19; 1 Corinthians 15:45–49). This means He could be our Savior.
• Being God in the flesh, Jesus knows experientially what it is to grow physically, to hunger and thirst, to be tired, and to feel pain. He also knows what it's like to be tempted (Hebrews 4:14–16). Not only did He reconcile us with Himself, but He understands what it is like to live in a world that so desperately longs for redemption and restoration. We know this world cannot be what is best.

implications for today

Jesus was executed by the Roman government, died, and was put into a tomb. Three days later, He came back to life! Jesus’s death was an acceptable sacrifice for sin—including your sin and my sin. If Jesus was merely a man, His sacrifice would have been just another death at the hands of the Romans. Instead, Jesus is fully human and fully God. He lived a human life without sin and did not inherit a sin nature because He did not have a human father. Thus, He could be a perfect and blameless sacrifice to atone for our sins. Because He is divine (God), He was able to overcome death, and His sacrifice covered all who call on Him for salvation (John 8:28–30; Hebrews 9:14–15; 10:1–18).