“By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God,” 1 John 4:2 (NKJV)
The false teachers that John was dealing with had somewhat of a unique perspective of who Jesus was. While they didn’t accept that He was God, they also didn’t deny that He was something supernatural. What they determined was that Jesus was less than God, but more than a man. He wasn’t God and He wasn’t a man. I guess you could say that they believed that Jesus was sorta a super powered angel. In the end what they did was deny His deity AND His humanity.
In 1 John 4:2 John says that to deny the humanity of Jesus is to deny Jesus. Yesterday we looked at the fact that Jesus is God. But it is absolutely critical that we understand that the nature of Jesus was that He was 100% God and that He was 100% man. He was God in the flesh. If we ever seek to downplay His deity to emphasize His humanity we make Him less that He is. If we ever seek to downplay His humanity to emphasize His deity we make Him less than He is. He was 100% God and 100% man. This is the miracle of the incarnation.
“For in Christ lives all the fullness of God in a human body.” Colossians 2:9 (NLT)
The word that is translated fullness basically means, “the sum total of all the divine power and attributes.” It means all the stuff that makes God God, was in Jesus. The word live means that wasn’t there temporarily, it was there permanently. It was something that had always been there and it was something that would always be there. One Greek scholar said that the word live meant that this fullness was, “not something added to His being that was not natural to Him, but that it was part of His essential Being as part of His very constitution, and that permanently.”
Why did Jesus have to be 100% God and 100% human?
“Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil,” Hebrews 2:14 (NKJV)
In order for Jesus to successfully die in our place, He had to be flesh and blood like we are. In order for His death to pay the penalty for the sins of the world, He had to be God. Jesus’ mission could only be accomplished if Jesus was God in the flesh.
We may wonder if this is really so very important. I mean, as long as we accept the deity of Jesus, is it really important to accept the humanity of Jesus? Yes it is.
“For many deceivers have gone out into the world who do not confess Jesus Christ as coming in the flesh. This is a deceiver and an antichrist. Look to yourselves, that we do not lose those things we worked for, but that we may receive a full reward. Whoever transgresses and does not abide in the doctrine of Christ does not have God. He who abides in the doctrine of Christ has both the Father and the Son. If anyone comes to you and does not bring this doctrine, do not receive him into your house nor greet him; for he who greets him shares in his evil deeds.” 2 John 1:7-11 (NKJV)
Those that deny the full humanity of Jesus are deceived and actually opposed to Christ. To deny the full humanity of Jesus is to go beyond the teaching of Jesus and prevents us from having fellowship with God. To depart from this doctrine is to depart from the faith. Anyone who teaches that Jesus is anything but 100% God and 100% man has departed from the faith. Any teaching that does not affirm this is fundamentally flawed and must be rejected.
For further study read John 1:11-14. What does verse 14 say that Jesus did? How does this relate to Jesus being God in the flesh?
Read Galatians 4:4-5. What happened when the fullness of time had come? Why did Jesus do this?
 Warren W. Wiersbe, Be Complete, pg 54
 Dr. Kenneth S. Weust, Ephesians and Colossians in the Greek New Testament, pg 187, quoted by Warren W. Wiersbe, Be Complete, pg 54