In John's letters (1 John 4, 2 John 1), he tells us that the spirit of the Antichrist denies the Incarnation (the Son of God becoming man) and thereby also the Trinity (the Father and the Spirit, too).
THIS IS THE SPIRIT OF ANTI-CHRIST. Funny how the Profits of Doom get all hung up on Revelation and Daniel and never consider these verses.
Then he doubles on the meaning by referring to the Antichrist as real people who were already in the world. (1 John 4:5) The people he is talking about have the spirit of the Antichrist, so its both spirit and people. So who was John talking about?
2 John 1:7 affirms 1 John 4:5. For John to have to repeat himself, these people must have been a headache for the early church. We know them as Gnostics, which is a term not used at that point in history. They cover a broad range of different schools and different sects, and predate Christianity, but it helps to take a look at what they believed before seeing what Paul had to say about them.
Gnostics believed matter was bad, therefore the body was evil and only the spirit was good. They believed in a strict separation of the two. That is why they deny Christ in the flesh, saying that He would never deign to incarnate into a fleshly body. In Gnostic asceticism we see both ends of the spectrum in their treatment of the body. Some Gnostics proposed that severe treatment of the body through rigorous denial of certain things was the way to deal with evil of the flesh. Others said that since flesh was evil but they had already attained the higher knowledge of the spirit, and since the two were separate, they could do anything they wanted in the body.
"...One form of Gnosticism was "Docetism," a heresy that threatened the young church. The Greek word "dokein" means "to seem," or "appear to be." Docetists believed that Jesus Christ was not a real man but only seemed to be so; according to them, He did not have a body, but simply passed through the Virgin without being fashioned of her substance...
...According to St. Irenaeus, Saturninus (c. 120) "declared that the Savior was unborn, incorporeal and without form ... For to marry and bear children, he says, is of Satan."Midway between the two extremes, the rigidly ascetic and the freely licentious, were Basilides and Valentinus. Basilides and his son Isidore allowed marriage on the ground that it is better to marry than to burn (cf. 1 Cor. 7.9), but marriage was to be avoided by the man who was ambitious to attain perfection. After his death, Basilides' followers departed from their master's teaching and fell into licentious ways, "by living lewder lives than the most uncontrolled heathen, they brought blasphemy upon his name." According to St. Irenaeus, Basilides taught that the practice of all lusts was a matter of indifference, and said, "Marrying and bearing children are from Satan."
Gnosticism, then, could not sanctify marriage as long as it had such an attitude towards matter and body; both, for the Gnostics, are evil. The
Gnostic texts of Nag-Hammadi agree that marriage and procreation, as instigated by archontic powers, have no place in the perfect life...
"The doctrine of Sanctification in relation to Marriage according to St. Athanasius," dealt with the Gnostics' view of marriage. He states that
St. Clement explained that the
Gnostic's duelist view of creation led to
two opposing attitudes toward marriage and sexuality: the extreme of a rigorous and negative asceticism on the one hand, and a licentious antinomianism on the other. Both repudiate nature; the one through abstention and the other through excess.
School of Alexandria and the Gnostics
The point of all this is the Gnostics forbid to marry. To them, marriage was evil. "They" are who Paul is talking about in 1 Tim. 4:3. Paul was celibate so he couldn't have been writing against himself. Same for "forbidding certain foods". To them, the food was evil. Plus they used their brand of unholy fasting as a holiness weapon over others.
So far, I have established that the Gnostics of John and Paul's day had the spirit of the Antichrist. Jesus had no body because the flesh is evil.
Ignatius of Antioch predates St. Irenaeus discourse against the Gnostics by a mere ten years. St. Ignatius became the third bishop of Antioch, succeeding St. Evodius, who was the immediate successor of St. Peter. He heard St. John preach when he was a boy and knew St. Polycarp, Bishop of Smyrna. Seven of his letters written to various Christian communities have been preserved. Eventually, he received the martyr's crown as he was thrown to wild beasts in the arena. He picks up where John leaves off:
"Consider how contrary to the mind of God are the heterodox in regard to the grace of God which has come to us. They (Gnostics) have no regard for charity, none for the widow, the orphan, the oppressed, none for the man in prison, the hungry or the thirsty. They (Gnostics) abstain from the Eucharist and from prayer, because they do not admit that the Eucharist is the flesh of our Savior Jesus Christ, the flesh which suffered for our sins and which the Father, in His graciousness, raised from the dead."
"Letter to the Smyrnaeans", paragraph 6. circa 80-110 A.D.
2 John 1:7 1 John 4:5 You might not get the connection with St. Ignatius. That's ok.