Context / meaning
1 John 2 [18.] Little children, these are the end times, and as you heard that the Antichrist is coming, even now many antichrists have arisen. By this we know that it is the final hour. They went out from us, but they didn’t belong to us; for if they had belonged to us, they would have continued with us. But they left, that they might be revealed that none of them belong to us. You have an anointing from the Holy One, and you all have knowledge. [c] I have not written to you because you don’t know the truth, but because you know it, and because no lie is of the truth. Who is the liar but he who denies that Jesus is the Christ? This is the Antichrist, he who denies the Father and the Son. Whoever denies the Son, the same doesn’t have the Father. He who confesses the Son has the Father also.
1 John 2 [24.] Therefore, as for you, let that remain in you which you heard from the beginning. If that which you heard from the beginning remains in you, you also will remain in the Son, and in the Father. This is the promise which he promised us, the eternal life. These things I have written to you concerning those who would lead you astray. As for you, the anointing which you received from him remains in you, and you don’t need for anyone to teach you. But as his anointing teaches you concerning all things, and is true, and is no lie, and even as it taught you, you will remain in him. Now, little children, remain in him, that when he appears, we may have boldness, and not be ashamed before him at his coming. If you know that he is righteous, you know that everyone who practices righteousness has been born of him.
c. 1 John 2:20 Or, “know what is true”, or, “know all things”.