1 John 4:3

and every spirit which does not confess Jesus [incarnate] does not come from God. This latter is the spirit of antichrist; you were told it was coming, and here it is already in the world.

1 John 2:18

Children, it is the last hour. You have learned that 'Antichrist is coming.' Well, but many antichrists have appeared ??which makes us sure it is the last hour.

1 John 2:22

Who is the real liar? who but he who denies that Jesus is the Christ? This is 'antichrist,' he who disowns the Father and the Son.

2 John 1:7

I say this, because a number of impostors have emerged in the world, men who will not acknowledge the coming of Jesus Christ in the flesh; that marks the real 'impostor' and 'antichrist.'

2 Thessalonians 2:3-8

Let nobody delude you into this belief, whatever he may say. It will not come till the Rebellion takes place first of all, with the revealing of the Lawless One, the doomed One,

Treasury of Scripture Knowledge

Summary

And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world.

General references

Bible References

And this

1 John 2:18
Children, it is the last hour. You have learned that 'Antichrist is coming.' Well, but many antichrists have appeared ??which makes us sure it is the last hour.
2 Thessalonians 2:7
For the secret force of lawlessness is at work already; only, it cannot be revealed till he who at present restrains it is removed.
2 John 1:7
I say this, because a number of impostors have emerged in the world, men who will not acknowledge the coming of Jesus Christ in the flesh; that marks the real 'impostor' and 'antichrist.'

General references

John 8:47
He who belongs to God listens to the words of God; you do not listen to them, because you do not belong to God."