In justification, God proves Himself Just and Holy by dealing justly as well as mercifully with sinners through the cross of Christ. On the cross, our sin was imputed to Christ, and he was thereby justly condemned; His righteousness was imputed to us, and we are justified. Justification indicates a permanent change in our judicial relation to God whereby we are absolved from the charge of guilt, and whereby God forgives all our sins on the basis of Christ’s finished work. Justification is a gift of grace (Rom. 3:24; Titus 3:7) that comes through faith (Rom. 3:28; 5:1). Christians receive Jesus (John 1:12) and put their faith-filled trust in what Jesus did on the cross (Isaiah 53:12; 1 Pet. 2:24) and in so doing are justified by God.  The Bible states that justification is not by works (Rom. 3:20, 28; 4:5; Eph. 2:8-9) because our righteous deeds are filthy rags before God (Isaiah 64:6).  Therefore, we are saved by grace alone, through faith alone, in Christ alone.

Roman Catholic theology teaches justification based on faith and effort as opposed faith alone. In other words, personal merit is required for justification as opposed to the merit of Christ alone.