The Westminster Confession of Faith (11.1-2) summarizes the Protestant position succinctly here, under girding the whole with irrefutable support from Scripture:

I. Those whom God effectually calleth, he also freely justifieth (Rom 8:30; 3:24), 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 (Rom 3:22-28; 4:5-8; 5:17-19; 2 Cor 5:19, 21 Tit 3:5, 7), 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; Eph 2:7-8).

II. Faith, thus receiving and resting on Christ and his righteousness, is the alone instrument of justification (Jn 1:12; Rom 3:28; 5:1); yet is it not alone in the person justified, but is ever accompanied with all other saving graces, and is no dead faith, but worketh by love (James 2:17, 22, 26 Gal 5:6).