Catholic
The Catholic Church teaches that justification is not only the remission of sins but also the sanctification and renewal of the inner person, making the sinner truly just. It holds that justification comes by God's grace through faith, but that faith must be living — 'working through charity' — and can be lost by mortal sin.
Source: CCC 1814; 1989–1995; cf. Council of Trent, Session VI, ch. 15 ↗
Orthodox
The Orthodox Church teaches that justification is the sinner's restoration to right relationship with God, inseparable from sanctification and accomplished through synergy — God's grace working together with the believer's free cooperation. It rejects any notion of justification as a merely legal fiction.
Source: The Orthodox Faith, Vol. I ↗
Lutheran
Lutherans confess that sinners are justified — declared righteous — freely by God's grace through faith alone, for Christ's sake, when they believe their sins are forgiven through Christ. This 'article by which the church stands or falls' holds that Christ's righteousness is imputed to the believer apart from works.
Source: Augsburg Confession, Art. IV ↗
Reformed
The Reformed tradition teaches that God justifies sinners by imputing Christ's perfect obedience and satisfaction to them, received by faith alone as the instrument — not as something the believer produces. It holds that this pardon is full and free, grounded in Christ's righteousness, not in any righteousness within the believer.
Source: Westminster Confession 11.1–11.2 ↗
Baptist
Baptists teach that justification is God's gracious and full acquittal, on principles of his righteousness, of all sinners who repent and believe in Christ. They hold that it brings the believer into a relationship of peace and favor with God.
Source: BFM 2000, IV.B ↗
Methodist
Methodists teach that justification is God's pardoning of sinners and acceptance of them as righteous, received through faith alone — yet faith that is living and produces good works. In the Wesleyan way, justification is inseparable from the new birth, in which the believer begins a transformed life.
Source: Articles of Religion, Art. IX; UMC What We Believe ↗