Romans 5:1 Therefore having been justified by faith, we have peace with God through our Lord Jesus Christ.
“…it is because we have been justified, says the Apostle–really and truly justified–out of faith, that we have this peace with God which we feel in our quieted souls, and exult in this hope of the glory of God in which we are now rejoicing. Not only the case of Abraham [Romans 4], but their own experience as well, will teach them then that it is out of faith and not out of works that God justifies the sinner.”
“The peace that steals into the heart of him who rests upon this Savior in faith, and the joy that exults upon his lips as he contemplates standing in him before the judgment-seat of God, are but the proper emotions of the satisfied conscience, and as such are the proof to us that God’s wrath is really appeased, his condemnation reversed, and his face turned upon us in loving acceptance in his beloved Son. Lastly, then, his experience of peace and joy is an irrefutable proof that this and no other is the just God’s method of justifying the sinner.” –Benjamin B. Warfield “Selected Shorter Writings” Vol. 2, “Paul’s Argument from Experience” p. 144, 151