The latter part of chapter 2 is chiastically arranged:

A. Children, antichrists coming, they went out, 2:18-19
B. You have an anointing, knowledge, 2:20
C. I have written, truth/lie, 2:21
D. Antichrist is liar, denies Son and Father, 2:22
E. Deny Son, deny Father, 2:23
D’. Abide in what you have, abide in Father and Son, 2:24-25
C’. I have written, those who deceive, 2:26
B’. You have an anointing, knowledge, 2:27
A’. Little children, Christ coming, remain, 2:28-29