Little children, it is the last hour. Just as you have heard that the antichrist is coming, so now many antichrists have appeared. This is how we know it is the last hour.
References for 1 John 2:18
They went out from us, but they were not really part of us. If they had been part of us, they would have stayed with us. But by going out from us, they showed they all are not part of us.
But you have an anointing from the holy one, and all of you know the truth.
I don't write to you because you don't know the truth but because you know it. You know that no lie comes from the truth.
Who is the liar? Isn't it the person who denies that Jesus is the Christ? This person is the antichrist: the one who denies the Father and the Son.
Everyone who denies the Son does not have the Father, but the one who confesses the Son has the Father also.
As for you, what you heard from the beginning must remain in you. If what you heard from the beginning remains in you, you will also remain in relationship to the Son and in the Father.
This is the promise that he himself gave us: eternal life.
I write these things to you about those who are attempting to deceive you.
As for you, the anointing that you received from him remains on you, and you don't need anyone to teach you the truth. But since his anointing teaches you about all things (it's true and not a lie), remain in relationship to him just as he taught you.