The early variances from the explanations of Scripture, strangely enough, were not of the Arian sort, that denied the Deity of Jesus Christ, survived in our day by such as the Jehovah's Witnesses. No, the early heresies had to do with the denial of Jesus' humanity.

Once a person has decided and believed from the heart that Jesus is God, it is next to impossible, except through faith given by the Holy Ghost, to see Him also as fully man, with all that that involves, except actual sin.

Belief systems denying the full humanity of Jesus rose up in the very century that the apostles still lived and taught! The apostle John had to address this error in his first epistle:

(4:3, in Textus Receptus) "Every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the antichrist, which you have heard was coming, and is now already in the world." (NKJV)

or 2 John v. 7: "For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ as coming in the flesh." (NASB)

It was another Jesus. There would be many other depictions of Jesus to be excluded from orthodoxy, but this was among the first.

Broadly speaking, this heresy was known as docetism. That's from the Greek dokeo which means to "seem", or "appear." That is, Jesus seemd to be a physical body, but that was just an appearance, an illusion. Therefore, Jesus was not really a man as we know men, but, as some will mistakenly quote Paul, Jesus came in the "likeness" of sinful flesh (Romans 8:3) and was made in the "likeness" of men (Philippians 2:7). Not really a man, but something else, which they cannot define.

The Greek here for likeness is a word that does mean "similar" in appearance. But notice how the apostle uses the word in reference to death and resurrection in Romans 6:5,

"We are united with Christ in the likeness of His death (in baptism) and shall be so united in the likeness of His resurrection." Our being raised with Christ is a true resurrection. Our being buried with Him in baptism is a true burial. The fact that the deaths and resurrections take a different form does not cancel out their reality.

Jesus was made in the likeness of men. He is the God-man and we are merely the men. But both of us share that manhood, and it is a real manhood. He was made like me, as far as humanity is concerned. He is a man.