There is no more happy exaltation of Jesus than 1 John 2:1-2. He is both the "comforter" or "advocate" and the "propitiation".
The sin problem remains unsolved until John explains the role of Jesus. He advocates for us with the Father. He himself is the means by which God forgives sin, satisfying the wrath of God against sin.
The new command is an old one -- Love one another. Your love is the leading spiritual indicator of whether or not you are a believer in Jesus (1 John 2:11).
The Antichrist is not a person, but many persons who deny Christ. The antichrist is anyone or anything that denies Jesus is the Christ come from God. The refusal to bow before the anointed King Jesus is paramount to denying God. To bow before Jesus is to have the Father and the Son and to be confident in judgment. It's that simple.