“Faith does not justify as it is a work, which would make a Christ of our faith; but faith justifies, as it lays hold of the object, viz. Christ’s merits” ~ Thomas Watson (1620-1686)
The doctrine of justification by faith alone has been called the article on which the church stands or falls. In other words, this doctrine is a big deal. That being said, it’s often not understood well by people in the church. Theologian and historian Alister McGrath brought this to my mind once again in his book Studies in Doctrine. He wrote:
A popular misunderstanding of the Reformation doctrine of justification by faith is that we are justified because we believe, that it is our decision to believe that brings about our justification. Here faith is understood as a human work, something which we do—and so we are justified on the basis of our works! This is actually the later doctrine, especially associated with seventeenth-century Arminianism . . . The Reformation doctrine affirms the activity of God and the passivity of humanity in justification. Faith is not something we do, but something divine that is wrought within us. Faith is the principal work of the Holy Spirit (Calvin), and it is through faith that Christ and all his benefits are received.
In reading this definition, I am reminded of how shocking this is to most people. Many Christians, I would assume, are confused by what McGrath says above. They probably think their justification (that is, their right standing with God) was brought about because they believed. To be sure, the benefits of the gospel are received by faith, but we are not justified because we believe. We are justified (declared to be righteous in God’s sight) because of Christ. Christ’s work on the cross is what saves us! By looking to Christ and trusting in him alone we are saved! As John Gerstner memorably puts it, “Justification is ultimately by works—the works of Jesus Christ!”
What brings confusion, I think, is that people assume (wrongly) that faith is meritorious. This is not the case, however. Faith looks completely away from oneself and looks only to Christ for righteousness. I love the way Joel Beeke says it: “The very act of faith by which we receive Christ is an act of utter renunciation of all our works and righteousness as a condition or ground of salvation.”
An important word in that last sentence is ground. What is the ground of our justification before God? The answer to this question brings into focus the realization that it can’t be my faith. The ground of my right standing with God is not my faith, for, as Don Kistler observes, “faith did not die on a cross and faith did not propitiate for anyone’s sins.” Christ did all these things! Thus, the ground of my right standing with God is Christ’s righteousness. For these reasons (and many more), it seems better to think of faith, not as a condition of justification but as the instrument through which we receive the benefits of the gospel. Even if one were to maintain that faith is a condition, “It is a condition which has in it no merit in itself, but which only seizes upon the merit of another,” namely, Christ.
Praise God that he saves us totally by his grace! And this salvation by grace is through faith. The two go together. As Paul says, “That is why it depends on faith, in order that the promise may rest on grace . . .” (Rom. 4:16). Why faith? Because faith is not a meritorious work that God rewards with salvation; faith, as Wayne Grudem rightly notes, essentially says, “I give up! I will not depend on myself or my own good works any longer. I know that I can never make myself righteous before God. Therefore, Jesus, I trust you and depend on you completely to give me a righteous standing before God.”
 Alister McGrath, Studies in Doctrine (Grand Rapids: Zondervan, 1997), 391.
 John H. Gerstner, “Justification by Faith Alone (The Nature of Justifying Faith),” in Justification by Faith Alone: Affirming the Doctrine by Which the Church and the Individual Stands or Falls, by Joel Beeke, et. al. 2nd ed. rev. ed. (Morgan: Soli Deo Gloria, 2003), 118.
 Joel Beeke, “Justification by Faith Alone (The Relation of Faith to Justification),” in Ibid., 65.
 Don Kistler, “Justification by Faith Alone (Where Addition Becomes Subtraction),” in ibid., 123.
 Beeke, “Justification by Faith Alone,” 62; Wayne Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Grand Rapids: Zondervan, 1994), 730.
 Grudem, Systematic Theology, 730.