God the Son became incarnate for the sake of our salvation (Phil. 2:5–11), displaying marvelously His love and grace. Yet we should not miss the necessity of the incarnation. By this we do not mean that it was necessary for the Lord to save us. His choice to redeem sinners was entirely free, and He was under no compulsion to save anyone. Having made the free decision to save us, God was bound by His own character and revelation to use specific means to save us. Among other things, this means that since man sinned, only man can pay the price for sin. Many Scriptures point us in this direction. First Corinthians 15:21, for example, tells us that "for as by a man came death, by a man has come also the resurrection of the dead." The fact that Jesus is God incarnate means that His work has an infinite significance and can be applied to all of His people. Nevertheless, the work itself can be effectual for human beings only if is performed by a human being.
Today's passage also reveals the necessity of the incarnation, showing that Jesus' work as a man procures salvation for us. Matthew 3:13–17 records our Lord's baptism by John in the Jordan River, and as we read the account we can relate to John's confusion. In verse 14, John essentially asks Jesus why He needs to be baptized. Actually, John wanted to deny baptism to Him, and we have to admit that John was not entirely off-base. After all, John preached "a baptism of repentance for the forgiveness of sins" (Mark 1:4), and John recognized that Jesus had no sins for which He needed to repent (Matt. 3:14). When it came to Jesus and John, if anyone needed a baptism for the remission of sins, it was John.
Jesus did not dispute John's point, for as the sinless God-man, there was nothing for which He needed to repent. Nevertheless, our Savior said His baptism was necessary "to fulfill all righteousness" (v. 15). This statement overflows with christological significance. First, it shows that by His baptism, Jesus fully identified with His people as their representative. He did the same things that we do, albeit without sin, so He can stand in our place. Second, by this act of obedience in being baptized, Jesus shows us that our salvation would not be possible through His death alone. We have broken God's commandments, and to make up for that, there must be full obedience to His statutes. John's baptism was a command God gave to His people, and so it had to be obeyed. If our Savior had neglected this rule, His obedience to His Father would have been lacking, and He could not have saved us.
Dr. R.C. Sproul also notes the importance of the Spirit's descent upon Jesus as showing that His work as a man redeems us. As God, Jesus always enjoyed the presence of the Holy Spirit, but as a man the Spirit came upon Him at a particular point to empower Him for ministry. As Dr. Sproul notes, "It's the human Jesus who is anointed by the Holy Ghost to fulfill this mission of the Messiah." Jesus lived for our salvation as much as He died for it.