Children, it is the last hour, and just as you have heard that antichrist is coming, even now many antichrists have arisen, by which we know that it is the last hour.
References for 1 John 2:18
They went out from us, but they were not of us; for if they had been of us, they would have remained with us. But [they went out], in order that it might be shown that all of them are not of us.
References for 1 John 2:19
And you have an anointing from the Holy One, and you all know.
I have not written to you because you do not know the truth, but because you do know it, and because every lie is not of the truth.
References for 1 John 2:21
Who is the liar except the one 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 [either]; the one who confesses the Son has the Father also.
[As for] you, what you have heard from the beginning must remain in you. If what you have heard from the beginning remains in you, you also will remain in the Son and in the Father.
And this is the promise which he himself promised us: eternal life.
These [things] I have written to you concerning the ones who are trying to deceive you.
And [as for] you, the anointing which you received from him remains in you, and you do not have need that anyone teach you. But as his anointing teaches you about all [things], and is true and is not a lie, and just as it has taught you, you reside in him.
References for 1 John 2:27