In its ordinary meaning this term does not refer to the origin of sin but to the guilt of Adam’s sin imputed to his offspring (hereditary guilt, Romans 5:12–19; Ephesians 2:3), and the corruption of man’s nature that occurred when sin entered and which inheres in the human will and inclinations. Let us read Genesis 5:3; 6:5; 8:21; Job 15:14; Psalm 51:5; John 3:6; Romans 14:23.
Original sin is not an activity but a quality, a state, an inherent condition. It exists, though there is no conscious, voluntary act of internal or external powers, of mind or body. It is the chief sin, a root and fountainhead of all actual sins.
There is also a distinction between man’s nature and original sin. No one except God alone can separate the corruption of our nature from the nature itself. Since the fall of Adam all men who are procreated according to nature are born in sin. That is to say, they are without fear of God, are without trust in God, and are concupiscent. And this disease or vice of origin is truly sin, which even now damns and brings eternal death on those who are not born again through Baptism and the Holy Spirit. “Concupiscent” is explained as “unable by nature to have true fear of God and true faith in God” (Augsburg Confession Article II).
Escape from the consequences of original sin is only by rebirth through Baptism and the Holy Spirit (Mark 16:16).
Separation of the corruption of our nature from the nature itself will take place wholly by way of death in the resurrection. Then the nature which we now bear will arise and live forever, without original sin and completely separated and removed from it. Read Job 19:26–27. Precisely the substance of this our flesh, but without sin, shall arise, and in eternal life we shall have and keep precisely this soul, although without sin. Christ will not quicken [original sin] in the elect, will not glorify it or save it. On the contrary, in the resurrection it will be utterly destroyed.