John tells us that the antichrists were ‘deceivers’ who had gone out into the world. This could mean they were Jewish missionaries who had gone out into the world to bring folks to believe in Judaism. Saul, before he became Paul, was one such Jewish missionary, as was Apollos, for the Jewish missionary system was quite prominent during the first century AD (cp. Matthew 23:15). Such were the “men from James” (or so they claimed, cp. Acts 15:22-27), and they were responsible for undoing Paul’s work among the Galatians (Galatians 2:11-14; 4:21-26), which prompted the need of the Jerusalem Council in Acts 15. On the other hand, 2John 1:7 may mean the antichrists were once among believers, but they left, showing they were never really believers at all (cp. 1John 2:18-19). Such an understanding would fit into Paul’s opinion that they were spies sent into the Church by the Jewish authorities to bring believers under the bondage of the Law and the authority of the high priest at Jerusalem (Galatians 2:4; cp. Acts 5:1-11, 13)!
The antichrists are false prophets (1John 4:1), called deceivers in 2John 1:7, and they deny that Jesus, the Christ, is coming in flesh. In other words they deny the power of the Messiah in the life of the believer, which is to say: they deny Jesus is coming in **our** flesh (cp. Colossians 1:27). Jesus is no ordinary king who rules from a seat of authority located somewhere in the world, which one could point to and say: “There is the place from which Jesus rules” (cp. Luke 17:20-21). No! Jesus’ seat of authority is within man and he rules our hearts, for he comes in our flesh. The antichrists **must** deny this, if they wish to promote the need for the Law. If Judaism is to exist at all, it must deny Jesus, the Christ, is coming in the flesh of believers. If gentile false teachers are to retain any power or authority over believers (and their funds), today, they **must** deny the power of Christ to lead the believer from within him. Antichrists deny the authority and power of Christ over his children.
John was very concerned over the elect lady and her children, not wanting them to lose their reward (2John 1:8). He wasn’t condemning them or threatening them with eternal punishment (love doesn’t threaten or make afraid; 1John 4:18), but he did point to the peril of losing what they had worked for in Christ (1Corinthians 3:11-15; cp. Hebrews 6:8). It was their reward, not their eternal life that John implied was in peril.
In order to get the full picture of what John is doing in 2John 1:9, we need to see it in the context of Jesus’ remarks about the wheat and the tares in Matthew 13:30, 41-43. John, as the Lord’s messenger (called angels in the text), was sent to separate the good from the evil. The tares, of course, are not the good seed, which the Lord planted (Matthew 13:24), but were planted by an enemy (Matthew 13:25). This fits in with what John had said earlier in 1John 2:18-19 about the antichrists. There he claimed that they went out from the people of God, but were not to be identified with the people of God. Rather, they were spies, sent in by an opposing authority (cp. Galatians 2:4; Acts 5:1-11, 13) in an effort to deceive the elect and conquer them in the name of the authority that sent them (cp. 2John 1:7; 1Peter 1:1-7), which Jesus earlier identified as the Jewish authorities at Jerusalem (Matthew 23:15, 29-36).
Thus, John differentiates the antichrists, who deny Jesus is coming in the flesh of the believer, from the believer who abides in the doctrine of Christ. The one is a deceiver who opposes the Lord, while the other walks in truth in obedience to the Father (2John 1:4). The one is a rebel whose end is to be destroyed (Matthew 13:42), while the other is a citizen of the Kingdom of God, which remains forever (Daniel 2:44).