"If we say we have no sin, we deceive ourselves and the truth is not in us." 1 John 1:8, ESV
This is precisely the intention of Augustine's definition that original sin is concupiscence. It means that when righteousness is lost, concupiscence follows. Since nature in its weakness cannot fear and love God or believe in him, it seeks and loves carnal things; either it despises the judgement of God in its security, or it hates him in its terror. Thus Augustine includes both the defect and the vicious disposition that follows. Concupiscence is not merely a corruption of the physical constitution, but the evil inclination of man's higher capacities to carnal things. They do not know what they are talking about when they simultaneously attribute to a man a concupiscence that has not been quenched by the Holy Spirit and a love for God above all things. In our definition of original sin, therefore, we have correctly expressed both elements: lack of ability to trust fear, or love God; and concupiscence, which pursues carnal ends contrary to the Word of God (that is, not only the desires of the body but also carnal wisdom and righteousness in which it trusts while it despises God). Apology of The Augsburg Confession, Article II, 23-26, Tappert.
"If we confess our sins, he is faithful and just to forgive our sins and cleanse us from all unrighteousness" 1 John 1:9 ESV
Note, then, as I have often said, that confession consists of two parts. The first is my work and act, when I lament my sins and desire comfort and restoration for my soul. The second is a work which God does, when he absolves me of my sins through a word placed in the mouth of a man. This is the surpassingly grand and noble thing that makes confession so wonderful and comforting. Luther, Large Catechism, A Brief Exhortation to Confession, Tappert.
