For now, here is something Perkins said that answers quite well our present-day justification controversy .
The doctrine which we teach on the contrary is that a sinner is justified before God by faith, yes, by faith alone. The meaning is, that nothing within man, and nothing that man can do, either by nature, or by grace, concurs to the act of justification before God, as an cause thereof, either efficient, material, formal, or final, but faith alone. All other gifts and graces, as hope, love, the fear of God, are necessary to salvation, as signs thereof and consequents of faith. Nothing in any man concurs as any cause to this work but faith alone. And faith itself is no principal, but only an instrumental cause whereby we receive apprehend, and apply Christ and his righteousness for our justification.