Okay, I have now read that section and will agree with his statement that John means what he says. One significant issue which you and I do not currently agree upon, and which the author passed over with no comment whatsoever, is the type of action indicated by the verbs in 1 John 1:8-10.
In the quote below of those verses the "we" refers to John, the Apostles, the intended recipient of the letter, in short it refers to all Christians. The verbs which are Aorist tense are only bold and indicate an undefined type of action. The take away is that the action occurred. The verbs that are Present tense are in red bold and indicate an ongoing or continuos action. The Perfect tense verbs are bold blue and the type of action indicated is, "that the progress of an action has been completed and the results of the action are continuing on, in full effect."
www.ntgreek.org
A convenient site to read brief summaries of the type of action indicated by a Greek verb tense is
here. A person will need to scroll down to verb tenses to read of the types of action.
“8. If
we claim (AAS) that
we have (PAI) no sin,
we are (PAI) deceiving ourselves, and the truth
is (P-I) not in us.9. If
we confess (PAS) our sins,
He is (P-I) faithful and just to
forgive (AAS) us our sins and
to cleanse (AAS) us from all unrighteousness. 10. If
we claim (AAS) that
we have (RAI) not
sinned,
we make (PAI) Him a liar, and His word
is (P-I) not in us.” (1Jo 1:8-10, EMTV)
So looking at verse 8, "If we claim," ever claim, "that we have no sin, we are deceiving ourselves," an ongoing or continuos action unless or until that false claim is repented of, "and the truth is not in us," this too is an ongoing or continuos action unless or until that false claim is repented of.
9. If
we confess our sins," if we do come to repentance of that false claim and confess our sins, an ongoing action, "
He is (P-I) faithful and just," an ongoing action, "to forgive us our sins and to cleanse us of all unrighteousness."
"10. If we claim," ever claim, "that
we have not sinned," the progress of the actions are completed with ongoing results, "
we make Him a liar," an ongoing action unless or until that false claim is repented of, "and His word
is (P-I) not in us," an ongoing action unless or until that false claim is repented of.
If a passage comes to mind that you think conflicts with what John wrote above then please post it so we can take a look at it.
Christ is our righteousness through faith, “Simon Peter, a bondservant and apostle of Jesus Christ, to those who have obtained like precious faith with us by the righteousness of our God and Savior Jesus Christ:” (2Pe 1:1, EMTV) He came to save sinners, “Faithful is this word, and worthy of all acceptance, that Christ Jesus came into the world to save sinners, of whom I am chief.” (1Ti 1:15, EMTV)
Please note that in the concluding passage, 1 Tim 1:15, that Paul wrote he is the chief of sinners rather than he was the chief of sinners.