What is justification?
Justification is an act of God’ s free grace unto sinners, (Rom. 3:22,24–25, Rom. 4:5) in which he pardoneth all their sins, accepteth and accounteth their persons righteous in his sight; (2 Cor. 5:19,21, Rom. 3:22,24,25,27,28) not for any thing wrought in them, or done by them, (Tit. 3:5,7, Eph. 1:7) but only for the perfect obedience and full satisfaction of Christ, by God imputed to them, (Rom. 5:17–19, Rom. 4:6–8) and received by faith alone. (Acts 10:43, Gal. 2:16, Phil. 3:9)
The Westminster Larger Catechism: With Scripture Proofs. (Oak Harbor, WA: Logos Research Systems, Inc., 1996).