1 John 1:8 states, "If we claim to be without sin, we deceive ourselves and the truth is not in us".
John sent this Epistle to the churches near Ephesus, where John spent his latter years. So he is talking about Himself and other believers.
From A Personal Study Bible Unveiling All God’s Fullness In All God’s Word
By Jack W. Hayford, ed., Spirit Filled Life Study Bible
1 John 1:8 also means that claiming to be without sin is self-deception and is not based on truth. The verse, and its follow-up in verse 9, emphasizes that the reality of sin requires Christians to continuously confess their sins to God in order to maintain fellowship with Him, and that through this confession, they receive forgiveness and cleansing. Denial of sin is presented as a lie and an act of self-deception that hinders spiritual growth.
Once we are born again of the Holy Spirit Jesus removes the desire to commit a sin unto death, such as breaking one of the Ten Commandments. I lost the desire to commit adultery when the Holy Spirit came upon me on 2/9/77. Up until then I was trapped in an affair and had no desire to quit, even though I tried every month, breaking up with him, then asking him back again. That is how weak our flesh is and how strong our sin nature is. But after being filled with the Spirit after I saw a vision (the first) and God spoke to me (8 sentences) and completely cleansed me of all unrighteousness, and poured what felt like warm oil from the top of my head to the bottom of my feet. I actually felt a dark heaviness leave my body and felt light as a feather. I was then strong as an ox and had absolutely no desire to commit a sin unto death ever again.
Those who are not filled with the power of the gospel, the Holy Spirit, are living a lie and cannot relate to what I just described. Mind you, I told you I had gone to church for nearly 30 years unsaved before being born again. Do you still need 1 John 1:9, the verse that equates to Peter's Acts 2:38, Repent, ...and you shall receive the gift of the Holy Spirit." That confession is only needed once! But false teachers are preaching to an auditorium of unsaved people who sin, repent, sin, repent, sin, repent ad infinitum! Which can you relate to? They have no power to walk away from sins unto death.
On the other hand, the born again believers walk in the Spirit and the mistakes they may make having to do with immature fruit of the Spirit (sins not unto death 1 John 5:16-17, just need to heed the check in their Spirit and stop doing what they were doing. That is enough. 1 John 1:7. Like I am doing with you. I apologize for making you feel bad, and will stop that behavior. As I've told you, I think you are smart and I want to work with you on the truth of the gospel. Yes, sinlessness has nothing to do with immature fruit of the Spirit, and everything to do with sins unto death. You can see the difference in Numbers 15:22-36. There was a sacrifice for unintentional sins (fruit), but NO sacrifice for sins unto death like my adultery. That level of sin is taken out of our nature and is the consummation you spoke of. Those sins unto death you NEED to confess using 1 John 1:9 to receive the Holy Spirit and be born again of the Spirit.
There is no need for anyone to feel hopeless and distraught even over "sinless perfection" as it doesn't have to do with what we DO. Jesus does it all! He is the Author and Finisher of our faith, not us. All we need to do is that first repentance and belief in Jesus, and then abide in Him. That is the most important thing we need to keep doing. Once the Holy Spirit is in you He gives you the opposite desire in your now clean nature to read His Word and dwell on Jesus. As we do that then it is Jesus, not us, who matures all the fruit of the Spirit in us. I have noticed after years on Christian forums that I am not the same poster as I used to be. Jesus is finishing me, by perfecting me unto holiness. Rev. 22:11.
By the way, there is a misunderstanding in the Church regarding repentance. I "turned away" from my affair month after month and
was not able to. THAT is the realization you must come to. We are weak and must ask Jesus to empower us to keep His word and to come into our soul. This is called integrity of heart. That helped me stop the monthly yo-yoing. I heard a sermon on integrity of heart and then told Jesus that I realize I am too weak to stop loving this man, so if He wanted this affair to stop, to make him break up with me, and give him the strength to stay away from me when I would try to get him back. Jesus answered that prayer (the first answer in my whole life) and one week later he did just that. Two weeks later I received the Holy Spirit.
By the way, the use of "we" and "I" as in Romans 7 and 8 is an eastern method. You're reading with a western mindset and it doesn't mean the same to us as the apostles meant it. So remember that. For instance, Romans 7:14-25 Paul uses I, as if he currently had a problem with sin. But a few sentences later Paul again uses "me" in Romans 8:2 which says he was now FREE from Romans 7:14-25. And John says in 1 John 2:1 " My little children, these things I write to you, so that you may not sin." Would he really mean what you think 1 John 1:8 means if we couldn't stop sinning as you believe? 1 John 1 from 5-10 is a Semitic contrast of light verses darkness. 6, 8 and 10 are darkness. 5, 7 and 9 represent light.