The Doctrine Of Justification

Those whom God effectually calleth, he also freely justifieth:
not by infusing righteousness into them, but by pardoning their
sins, and by accounting and accepting their persons as righteous;
not for anything 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, they
receiving and resting on him and his righteousness, by faith; which
faith they have not of themselves, it is the gift of God.
WCF Chap 11 Sec 1