From Jeff's comment:
-Our sins are forgiven on the basis of a righteousness that is not our own, but is had by being ‘in Christ’, by faith (Phil 3)...
-It is ‘us in Christ’ and not ‘Christ in us’, that is the basis for our acceptance as God’s children.
When it comes to understanding the argument for imputed righteousness against that of infused righteousness, the above sentences point to a crucial theme of Paul's summed up in the two words 'in Christ.' That theme is found clearly Romans 6. Here, it seems to me, Paul is strongly making the case that it is 'in Christ' that the believer receives the benefits of Christ's death and resurrection because His death is our death, His resurrection is our resurrection. His penalty-paying is accounted to us. We paid the penalty for sin in Christ. His vindication/justification in His resurrection is our justification.
Several key phrases that Paul uses in the first part of chapter six of Romans:
- all of us who have been baptized into Christ Jesus have been baptized into His death
- buried with Him through baptism into death
- united with Him in the likeness of His death
- we shall also be in the likeness of His resurrection
- our old man was crucified with Him
- for he who has died is freed from sin.
- For the death that He died, He died to sin once for all
In those phrases, as well as others, imputation and substitution are interwoven into Paul's presentation of the good news of reconciliation to God of sinners in Christ Jesus. Good news that the penalty for sin is paid in Christ... there is forgiveness of sins in Christ... and sinners are reckoned righteous through faith in Christ.
The righteousness that comes from God is not an infused-righteousness to be found within the believer, as if it were his own. Rather it is the righteousness of Christ imputed to the believer, when by grace he is "found in Him, not having [his] own righteousness, which is from the law, but that which is through faith in Christ, the righteousness which is from God by faith..." (Phil. 3:9).
- A couple added thoughts from an earlier post in 2010:
And although Christians, as recipients of a new heart and right-will through regeneration by the Holy Spirit, may by His grace exhibit the fruit of godliness on many occasions, yet never in this life do they own inherent godliness within themselves.
Godliness and salvation are in Christ alone, received and held through faith in Christ alone by God's efficacious work of grace in our hearts. No work of merit on our part secures them nor maintains them.