1 John 4:3

Christian Standard Bible Anglicised

but every spirit that does not confess Jesus  is not from God. This is the spirit of the antichrist,  which you have heard is coming; even now it is already in the world.

Cross References

1 John 2:22

Who is the liar, if not the one who denies that Jesus is the Christ?  This one is the antichrist: the one who denies the Father and the Son.

2 John 1:7

Many deceivers have gone out into the world; they do not confess the coming of Jesus Christ in the flesh.  This is the deceiver and the antichrist.

1 John 2:18

Children, it is the last hour.  And as you have heard that antichrist  is coming, even now many antichrists have come. By this we know that it is the last hour.

Matthew 24:5

For many will come in my name, saying, “I am the Messiah,” and they will deceive many.