To which I counter
that is how we stand in this age, before Christ returns. And by stand I mean both our position before God as justified, and our perseverance to the end because we can no longer be condemned. When Christ returns all the wicked unbelievers, Satan, the source of all evil, and all his own spiritual (real but invisible) army are destroyed; gone; wiped out of existence in any place but the lake of fire. Impotent. And we who are in Christ, both those who are resurrected having already died, and those who remain alive at his coming, are changed. No longer able to die and no longer
corrupt or corruptible. We got there by the imputed righteousness of Christ. But then we are truly righteous, otherwise God would not dwell with us as he does in Rev 21 and as he did in Eden.
What Christ accomplishes on the cross is not only the forgiveness of our personal sins but also the imputed sin of Adam. That is why we are said as believers, to be in Christ. The "in Christ" is the opposite of what it is to be "in Adam." God takes his children out of Adam through the work of Christ, and places us in the Son. That is
why his righteousness is imputed to us, to keep us in him while we await his return. It is a right now, not yet situation. All those who are elected to be in Christ must be gathered first.
Because he is making us truly righteous. The imputed righteousness carries us to that state of being truly righteous. Truly righteous will never sin again, nor can it, because there is no sin at that point.
It changes because we are changed, (1 Cor 15).
Yes, though to say "it will be our righteousness" can be taken in different ways. We will be actually righteous---that is, sin will no longer be a part of us in our nature or in our actions, or anywhere else. We won't be in Adam anymore and we still are, in our flesh, right now. We still live in the fallen world, We are still fallen. We still have the same enemies----the world, the flesh, and the devil. We are kept for Christ, sealed in him by the Holy Spirit indwelling us, through imputed righteousness, through faith. So it is not our righteousness at the consummation, in the sense that we obtained to it on our own. It comes from the person and work of Christ. But it is real righteousness.
It is imputed now. That is, counted as though it is our own in the eyes of God. It gives us access to him and reconciles us to him, but this age is not the end of the story. It is the age we must travel through and we can only do so safely beneath the shadow of his wings, as his children and members of his household, to the promised land which is described in Rev 21, without being condemned to face his judgement and wrath. We were given to Jesus and his imputed righteousness is what keeps us in him until he returns.