When does God impute righteousness to a person?
God imputes His righteousness as soon as a person believes the Gospel. It is a heart belief, not mere head knowledge, that brings righteousness. When one believes with all their innermost being that Christ died for them, God imputes His righteousness and clothes them with Christ's righteousness.
Les explains that Romans 10:10 says with the heart man believes unto righteousness. He emphasizes self-examination: is it just head knowledge, or are you believing with all your innermost being that Christ died for the world and for you? As soon as we believe the Gospel, God imputes His righteousness. Les connects this to Genesis, where God killed animals for Adam and Eve, gave them coats of skins, and clothed them with righteousness. He also points to Isaiah 61, where the believer is clothed with garments of righteousness, and to Romans 3, where Paul says the same happens unto all that believe. Thus God clothes the believer with the righteousness of Christ the moment they believe.
For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation.