Abide in the Truth (1 John 2: 18 - 27)

Therefore let that abide in you which you heard from the beginning. If what you heard from the beginning abides in you, you also will abide in the Son and in the Father.

And this is the promise that He has promised us—eternal life.
These things I have written to you concerning those who try to deceive you.

But the anointing which you have received from Him abides in you, and you do not need that anyone teach you; but as the same anointing teaches you concerning all things, and is true, and is not a lie, and just as it has taught you, you will abide in Him.

Whoever denies the Son does not have the Father either; he who acknowledges the Son has the Father also.

But you have an anointing from the Holy One, and you know all things.

I have not written to you because you do not know the truth, but because you know it, and that no lie is of the truth.
Who is a liar but he who denies that Jesus is the Christ?

He is antichrist who denies the Father and the Son.

Abide in the Word(in me) and I will abide in you; our Lord promised us.

In this portion of the second chapter in 1John we are urged to abide in the Word as this is the mark that will separate us from the anti-christ.

If anyone comes to us and the Word is not in them, they speak a different truth to the one we learnt about from the beginning (John1) then we know they are against our Lord.