The Spirit Of The World; 1 Cor 2:12

1John 4:
1 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, for many false prophets have gone out into the world.
2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God,
3 and every spirit that does not confess Jesus is not from God. This is the spirit of the antichrist, which you heard was coming and now is in the world already.
4 Little children, you are from God and have overcome them, for he who is in you is greater than he who is in the world.
5 They are from the world; therefore they speak from the world, and the world listens to them.
6 We are from God. Whoever knows God listens to us; whoever is not from God does not listen to us. By this we know the Spirit of truth and the spirit of error.

"Greater is he that is in you"; the preposition "in" from the Greek does not mean "he that dwells within you individually" John is not speaking of the indwelling of the Holy Spirit. He is speaking of those who have remained in the fellowship as compared to those who have gone out into the world to preach another christ, through another gospel, by another spirit. (2 Cor11:4) These are the antichrists, the false prophets, and they speak by the spirit of antichrist The world receives their message gladly as the "Jesus" they preach is just another version of the golden calf. They are of the world and though they may remain with the saints for awhile, they end up going back to where they belong. Greater are those who remain in fellowship, proclaiming the true Christ and His Gospel, through the Word of God. revealed by the Holy Spirit. Greater are these than those who return to the world. Let the 'super apostles" and their ilk depart. (2 Cor11:12-13)
(By the way the fellowship that John is speaking of is not a particular institution, denomination, or sect that many people spend their time hopping in and out. He is speaking of the Body of Christ whoever and wherever they may be)

1John 2:
18 Children, it is the last hour, and as you have heard that antichrist is coming, so now many antichrists have come. Therefore we know that it is the last hour.
19 They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us.

2Peter 2:
18 For, speaking loud boasts of folly, they entice by sensual passions of the flesh those who are barely escaping from those who live in error.
19 They promise them freedom, but they themselves are slaves of corruption. For whatever overcomes a person, to that he is enslaved.
20 For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overcome, the last state has become worse for them than the first.
21 For it would have been better for them never to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them.
22 What the true proverb says has happened to them: "The dog returns to its own vomit, and the sow, after washing herself, returns to wallow in the mire."