For a child will be born to us, a son will be given to us; and the government will rest on His shoulders; And His name will be called Wonderful Counselor, Mighty God, Eternal Father, Prince of Peace. (Isaiah 9:6)
If Jesus was fully human, why did He also need to be fully God? Although we needed a blood relative to redeem us, we also needed God.
The former covenant with its regulations on sacrifices was unable to “perfect the conscience of the worshiper” (Hebrews 9:9). Because Christ was (and is) God, He was able to enter the tabernacle that was unreachable by human means. Because He was perfect He was able to enter heaven and act as the Mediator on our behalf. His sacrifice paid for sins once and for all and abolished the need for repeated sacrifices and reminders of sin. Only God is perfect and could offer us perfection. (Hebrews 9:11–10:18)
Hosea 13:4 summarizes this truth that is taught throughout Scripture: “Yet I am the LORD your God ever since the land of Egypt, and you shall know no God but Me; for there is no Savior besides Me.” New Testament writers also pointed out that God alone is the Savior (1 Timothy 2:3; 2 Peter 1:1). So we see that our Savior had to be and was indeed God.
There is another reason why the Savior had to be God. The just punishment for sin is eternal separation from God. Our sin makes us guilty and separates us infinitely from a perfectly righteous God. Since no finite number of good thoughts and actions can bring us closer to an infinite righteousness, we needed an infinitely atoning sacrifice that would cover all of our sins for all time—past, present, and future.
Since Jesus was also God, He was able to pay the infinite penalty for us and thus provide a bridge between us and God the Father. Only God could take the sins of the whole world upon Himself and wash our sin stains as white as snow.
"For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him.” (2 Corinthians 5:21)
Christ was the perfect sacrifice whose perfection is granted to all who receive Him by faith. His infinite sacrifice means that we would no longer have to be separated from God as we deserve.
Jesus is God, and His infinite, eternal sacrifice covers all our sins—past, present and future.
Thank God He came to earth to pay the infinite punishment for us so that the gap would be bridged and we can now come before Him.