Lets compare one verse,
1 John 4:3:
NIV - but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world.
RSV - and every spirit which does not confess Jesus is not of God. This is the spirit of antichrist, of which you heard that it was coming, and now it is in the world already.
ASV and every spirit that confesseth not Jesus is not of God: and this is the spirit of the antichrist, whereof ye have heard that it cometh; and now it is in the world already.
KJV - 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.
We see here in
1 John 4:3 that the NIV takes out the whole point in the text, "NIV leaves out the fact that Jesus Christ is come in the flesh--yet another swipe at the divinity of Christ."
https://mundall.com/erik/NIV-KJV.htm