Martyn Lloyd-Jones wrote, "In justifying us God tells us that He has taken our sins and our guilt, and has imputed them to, put them to the account of, the Lord Jesus Christ and punished them in Him. He announces also that, having done that, He now puts to our account, or imputes to us, the perfect righteousness of His own dear Son."
God justifies us by faith alone in Christ alone. We are justified from all sin at the cross of Jesus (1 John 1:7). Then, God puts the righteousness of Christ on our account. As Lloyd-Jones declared, "He now puts to our account, or 'imputes' to us, the perfect righteousness of His own dear Son."
Martin Luther focused upon the doctrine of justification by faith in Christ. He referred to it as the great exchange. Believers exchange their sins for the righteousness of Christ. Augustus Toplady, called it the double cure in his hymn, Rock of Ages. We sing these words: "Be of sin the double cure, save from wrath and make me pure." That's when God justifies us.
God justifies us through faith in the gospel of Jesus Christ. By faith in Jesus Christ our Lord, believers are justified from all sin (Romans 5:1). But, God does even more for every believer. He puts the righteousness of Christ on our account (2 Corinthians 5:21). Yes, our record of sin is wiped clean, and God also accounts us righteous in Jesus Christ (Romans 5:17-19).