Be on Guard Against the Enemies of Christ - 1 John 2:18-20

Children, these are the last days; you were told that an Antichrist must come, and now several antichrists have already appeared;

we know from this that these are the last days.

Those rivals of Christ came out of our own number, but they had never really belonged; (1) if they had belonged, they would have stayed with us;

buy they left us, to prove that not one of them ever belonged to us.

But you have been anointed (2) by the Holy One, and have all received the knowledge.

(1) Though they seemed to belong to the community, they lacked the spirit of Christ.
(2) In the O.T. the chrism that was to anoint the Messiah (the 'anointed') was identified with the (Holy) Spirit or Breath of Yahweh. Christians share in this anointing that teaches them the true gnosis or knowledge.