"All that can be said of us is that without this perfect action of God we would be lost; that apart from it we can have no refuge or counsel or consolation or help. But of God we have to say that this perfect action which He Himself did not need has in His merciful good pleasure taken place for us; that He willed to make it and did make it a need of His, a matter of His own glory, to do this for us, that is, to accept the perfect sacrifice, the righteousness of Jesus Christ as our righteousness, our sacrifice, and therefore as the finished work of our reconciliation. Not only as though we had brought this sacrifice, but as the sacrifice which we have brought. Not only as though the righteousness of Jesus Christ were ours, but as the righteousness which we have achieved. Not only as though the work of reconciliation finished in Him were our work, but really as the work which we have done. We remember that in the sacrifice of Jesus Christ we no longer have a substitute for that which we cannot do. It is no longer a question of a Quidproquo, an 'as if,' beyond which we still need something more perfect, a real reconciliation which has still to come. In the doctrine of the justification of man, of the reach of that which has taken place in Jesus Christ, we have to see that we are saying far too little when we use a favourite expression of the Reformers and call it an imputation of the alien righteousness of Jesus Christ. It cannot in any sense be an improper justification of man which has its basis in this happening. Otherwise how could it be a perfect happening, and how could the love of God for man realised in it be a perfect love? Rather, the alien righteousness which has been effected not in and by us but in the sacrifice of Jesus Christ does become and is always ours, so that in Him we are no longer unrighteous but righteous before God, we are the children of God, we have the forgiveness of our sins, peace with God, access to Him and freedom for Him. That this is the case is the righteousness which Jesus Christ has accomplished for us, the perfection of His sacrifice which cannot be added to by anyone or anything. He has sacrificed in our name with a validity which cannot be limited and a force which cannot be diminished. What He has done He has done in order that being done by Him it may be done by us; not only acceptable to God, but already accepted; our work which is pleasing to Him; our own being as those who are dead to sin and can live to righteousness. He alone has done this, but because He has done it, in a decision which cannot be reversed, with a truth which is absolute, He has done it for us."
Karl Barth, CD IV/1, 282-283.