1 John 2:18 Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
1 John 2:22 Who is a liar but he that denieth that Jesus is the Christ? He is antichrist, that denieth the Father and the Son.
1 John 4:3 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.
2 John 1:7 For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.
Christadelphians believe that the antichrist is embodied in those churches that teach that Christ is God and that when he was born of Mary he had a ‘dual nature’. The antichrist falsely claims that Jesus is ‘one substance’ with his Father, that he was not just a man, but ‘wholly man’ and at the same time ‘wholly God’; which is an impossibility.
The Bible teaches that Christ was born a man with exactly the same nature as we have. He was tempted to sin exactly as we are (God cannot be tempted to sin). He died because he was mortal exactly as we are.
When he was dead he had no conscious existence, and had God not raised him from the dead he would have perished forever. This being the case, the antichrist has been in power in the Church since the fourth century AD when the false doctrine of the Trinity was adopted.
The teaching that we are still waiting for the antichrist to arise is a ‘cover-up’ to obscure the reality that Christianity has been mired in apostasy and in the grip of the antichrist for centuries.
I hope you find this helpful.