How doth faith justify a sinner in the sight of God?
Faith justifies a sinner in the sight of God, not because of those other graces which do always accompany it, or of good works that are the fruits of it, (Gal. 3:11, Rom. 3:28) nor as if the grace of faith, or any act thereof, were imputed to him for his justification; (Rom. 4:5, Rom. 10:10) but only as it is an instrument by which he receiveth and applieth Christ and his righteousness. (John 1:12, Phil. 3:9, Gal. 2:16)
The Westminster Larger Catechism: With Scripture Proofs. (Oak Harbor, WA: Logos Research Systems, Inc., 1996).
The catechism clearly says that faith is not an act that is imputed for justification. It is an instrument, means, or tool by which God applies to us the sinless perfection of Christ and his righteousness. The active obedience of Christ alone can merit anything whatsoever from God. -- Charlie
Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent. (John 6:29 KJV)