WSC Q.33: What is justification?
Justification is an act of God’s free grace, wherein he pardoneth all our sins, (Rom. 3:24–25, Rom. 4:6–8) and accepteth us as righteous in his sight, (2 Cor. 5:19,21) only for the righteousness of Christ imputed to us, (Rom. 5:17–19) and received by faith alone. (Gal. 2:16, Phil. 3:9)
WLC Q.70: 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)
WCF 11.1.
Those whom God effectually calleth, He also freely justifieth: (Rom. 8:30, Rom. 3:24) not by infusing righteousness into them, but by pardoning their sins, and by accounting and accepting their persons as righteous; not for any thing wrought in them, or done by them, but for Christ’s sake alone; nor by imputing faith itself, the act of believing, or any other evangelical obedience to them, as their righteousness; but by imputing the obedience and satisfaction of Christ unto them, (Rom. 4:5–8, 2 Cor. 5:19,21, Rom. 3:22,24–25,27–28, Tit. 3:5,7, Eph. 1:7, Jer. 23:6, 1 Cor. 1:30–31, Rom. 5:17–19) they receiving and resting on Him and His righteousness by faith; which faith they have not of themselves, it is the gift of God. (Acts 10:44, Gal. 2:16, Phil. 3:9, Acts 13:38–39, Eph. 2:7–8)