1 John 1:9 If we confess our sins, he faithful and just to forgive our sins, and to cleanse us from all unrighteousness.
God promises absolutely that He will most certainly forgive us all our sins and cleanse us from all our unrighteousness within. The Lord fervently desires to dwell in us and to live His life in us and through us. But He cannot live in a place that is corrupted by sin and self. So He makes a holy place inside so that He can dwell there and influence our sinful soul unto love and good works. Therefore, He forgives completely.
We may not always feel totally forgiven and thoroughly clean, but we are. The Holy Spirit creates and grows faith through the Gospel. Thus we know we are forgiven when the Lord says, ”I forgive you!” We get up and walk away clean. We believe it. We believe because God says so, and He is faithful to His Word and Promise. We can count on Him to do what He says. He is also just to forgive. It is just and right for God to forgive, for justice has been served; all our sins were totally and forever judged and punished at the cross when Jesus took our sins upon Himself, and died. God does not just overlook and ignore sin and guilt. He justly and actually forgives.
”If we confess” means repentance and faith in the gospel. We are always in a state of grace and always forgiven. But we still need reminders, so we confess daily and weekly because we live with sinful flesh in a corrupt world with an accusing Satan. And God forgives, again and again. Particularly when we feel guilty and dirty we may confess sins and receive absolution. God faithful to forgive.