While justification is an act of God and is something he graciously does on behalf of sinners, this does not mean human beings are passive in every respect. Human beings must believe in Jesus. Upon believing, God’s response is to justify the ungodly (Rom 4:5). This exercise of faith is not a work that seeks to earn, but receives the salvation that is freely offered in Jesus. In John 1, believing is parallel to receiving. “He came to his own, and his own people did not receive him. But to all who did receive him, who believed in his name, he gave the right to become children of God, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God” (John 1:11–3).
Thus, to receive Jesus is to believe in Jesus and in some sense is, according to Calvin, passive. Calvin writes, “For with respect to justification, faith is a thing merely passive, bringing nothing of our own to conciliate the favor of God, but receiving what we need from Christ.” Though Calvin says faith is “passive,” he does not mean that there is no act of the will. Instead, he means that faith is “passive” in the sense that it does not actively pacify (“conciliate”) God. Instead, faith receives or apprehends Christ, who is the propitiation for our sins (cf. 1 John 2:2; 4:10).
In addition to describing faith as a receiving of Christ, the Reformed tradition borrows from Aristotelian categories to explain faith as the instrumental cause that leads to God’s gracious act of justification (Rom 5:1). Again, Calvin strikes the correct note when he writes, “faith of itself does not possess the power of justifying, but only in so far as it receives Christ.” In other words, faith is the instrument by which the sinner takes hold of Christ. The Belgic Confession states, “faith is an instrument that keeps us in communion with [Christ] and all His benefits…” The WCF agrees, “Faith, thus receiving and resting on Christ and his righteousness, is the alone instrument of justification.”
Some, however, have objected to the idea of calling faith the instrumental cause. John Owen notes that the hesitancy of some is due to the “unscriptural notion” of this Aristotelian category. Owen responds by reminding his readers that this hesitation is unwarranted and cites the classical understanding of God as “a trinity of persons” as evidence that Christians have often used words and concepts outside the pages of Scripture to make sense of theological realities. Thus, to say that faith is the instrumental cause of our justification uses available philosophical concepts to capture the biblical reality and Reformed position that though faith is a human act, it merely takes hold of Christ, who is the sole ground of our justification. That is, justification does not depend on the intrinsic value of faith. Instead, our confidence is sought “only in the terrors of Christ our Redeemer,” who is apprehended by faith alone. The Belgic Confession states the point clearly when it says, “we do not mean, properly speaking, that it is faith itself that justifies us—for faith is only the instrument by which we embrace Christ, our righteousness.”
Therefore, faith was and is considered a human act that takes hold of Jesus. Of course, the act of faith is itself a gift of grace (Eph 2:8–9). Though there is some debate about what “the gift” (Eph 2:8) refers to specifically in Ephesians 2, it seems best to take salvation as a whole as the antecedent. Yet, the gift certainly includes faith since “by grace you have been saved through faith” (Eph 2:8). Therefore, the faith that we place in Jesus is not something men and women conjure up in their own power. Given what we have noted in a previous post about the priority of grace, the will cannot move in faith towards God on its own apart from God’s internal work of grace. Instead, faith is a gift and Spirit-wrought human act, the “principle work of the Holy Spirit.”
Furthermore, this act is not a simple act. For the Reformed, the act of faith involved various elements. For instance, the Reformed tradition believed faith included notitia, assensus, and fiducia. That is, the exercise of faith included knowledge of certain realities, assent to their veracity, and a trust in a person, namely Jesus. In addition to knowledge, assent, and trust, faith was described in the tradition as including various faculties of the soul. This point is important and deserves more attention (perhaps a future post). Here it is sufficient to provide one example of a Reformed theologian who spoke of faith as a complex act of the soul. Peter van Mastricht, a Reformed theologian held in high esteem by many (including Jonathan Edwards), described the act of faith in diverse ways. He writes, “We call this faith an act—an act of the rational soul that consists in receiving God as the end and Christ as the Mediator.” This act of the soul was “of the whole soul” and included each of the “soul’s faculties—the intellect, the will, the affections, and so forth.” This sort of description is not novel in the tradition and is evidence that for the Reformed, this act of faith was more than a simple acknowledgment of truth. My hope is to return to this point in a future post in order to dissect in more detail the ontological character of justifying faith. For now, we simply conclude that the Reformed tradition believed mankind must exercise faith, an act that included various faculties of the soul if they would be justified before God.
To say, however, that we are justified by grace through faith is not in and of itself controversial, at least for Christians who read the Bible. Rome and the Reformers could both assert justification by faith. The point of contention between Protestants and Catholics is felt when the word “alone” is added to the discussion. Luther had included the word “alone” or “only” in his 1522 translation of the New Testament. Luther translated Rom 3:28 as, “We hold, therefore, that someone becomes righteous without the work of the law, only through faith.” Though Luther seems to understand justification in transformative terms at this point in his ministry (he is, after all, a Medieval man groomed in Augustinianism), the important point here is the introduction of the world “only.” It is beyond our purposes here to evaluate Luther’s translation. The historical-theological importance is our main concern and was not something missed by Roman Catholics.
At the Council of Trent, the idea that we are justified sola fide is explicitly condemned. According to Rome, faith was a necessary but not a sufficient condition for justification. As De Chirico notes,” According to Trent, faith alone is an anthropological impossibility… a soteriological conundrum…[that] excludes the primary and necessary sacramental mediation of the church.” In other words, sola fide led sinners away from the sacramental system when it came to how one could be counted righteous before a holy God. Rome could not countenance a position that undermined the centrality of the Church in the salvation of sinners. Yet, the Reformed tradition has vigorously defended the assertion that sinful men and women are justified by faith alone, apart from any internal worth or merit, or any necessary participation in the sacraments of the Church.
Moreover, though the phrase “justification by faith alone” does not exist in the Bible, that does not mean the phrase fails to capture the biblical idea. The Reformed tradition has spilled large amounts of ink to drive the theological point home. John Calvin engages with “the Sophists” who “dare not deny that man is justified by faith because it recurs so often in Scripture.” Yet, “since the word “alone” is nowhere expressed, they do not allow this addition to be made.” He takes up the objection of the Sophists who say that justification apart from “works of the law” refers specifically to the ceremonial works of the law…not the moral works.” Calvin disagrees. He quotes several passages from Paul (Gal 3:10, 12, 21–22; Rom 3:20, 27; 4:4–5, 15) to show how Paul has “the whole law” in view. The moral and ceremonial laws are excluded and therefore “Not only by a false but by an obviously ridiculous shift they insist upon excluding this adjective [i.e. alone].” For Turretin, faith alone made sense because it pointed towards the reality that our only hope is the righteousness of Christ, and faith “alone apprehends” this righteousness. Taking hold of the righteousness of Jesus did not come through the keeping the law or exerting moral effort, but “by faith alone.”
In summary, Paul’s inference in Rom 5:1 is plain enough. “Therefore, since we have been justified by faith, we have peace with God through our Lord Jesus Christ.” The Reformed tradition has followed suit, asserting that justification is by grace through faith alone because it alone apprehends Christ and his righteousness. Therefore, the Heidelberg Catechism asks: “How are your righteous before God?” Answer: Only by faith in Jesus Christ…” Indeed, the only hope for humanity is to take hold of Christ by the instrumental means of sola fide. And, of course, this faith that justifies will not be alone, as justified men and women give their lives to loving God and loving neighbor.
 Calvin, Justification, 3.5.
 Ibid., 1.4. The doctrine of propitiation refers to how Christ has satisfied the wrath of God by dying in the place of sinners. Grudem states that propitiation is “a word that means “a sacrifice that bears God’s wrath to the end and in so doing changes God’s wrath towards us into favor” (Wayne A. Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Leicester, England: Grand Rapids, MI: Inter-Varsity Press ; Zondervan Pub. House, 1994), 575). A detailed linguistic study is found in Leon Morris, The Apostolic Preaching of the Cross, 3. ed., reprint. (Grand Rapids, MI: Eerdmans, 1987).
 The language of instrumental means is common language in understanding the doctrine of justification. Calvin writes, “I say that faith, which is only the instrument for receiving righteousness… (Calvin, Institutes, 734). See Marcus Peter Johnson, One with Christ: An Evangelical Theology of Salvation (Wheaton, IL: Crossway, 2013) 99–100. Jonathan Edwards, however, is unique in his choice to talk about how faith makes it fitting that God declares us just. For discussions of Edwards position, see Josh Moody, ed., Jonathan Edwards and Justification (Wheaton, IL: Crossway, 2012).
 Calvin, Institutes, 733. Wayne Grudem writes, “Scripture never says that we are justified because of the inherent goodness of our faith, as if our faith has merit before God. It never allows us to think that our faith in itself earns favor with God. Rather, Scripture says that we are justified “by means of” our faith, understanding faith to the instrument through which justification is given to us, but not at all an activity that earns us merit or favor with God” (Grudem, Systematic Theology, 730).
 Peter Martyr Vermigli writes that “we are said to be justified by [faith] because through it we take hold (apprehendimus) of the promises of God and the righteousness and merits of Christ, and apply them to ourselves” (Peter Martyr Vermigli, Locus on Justification, 96, quoted in Horton, Justification, vol. 2, 264–265).
 Belgic Confession, Article 22.
 WCF, 11.2
 John Owen, The Works of John Owen. 5: Faith and Its Evidences, ed. William H. Goold, 5. printing; Repr., Johnstone & Hunter, 1850-53. (Edinburgh: Banner of Truth Trust, 1998), 108–109.
 Horton, Justification, vol. 1, 263.
 Calvin, Justification, loc. 1062.
 Belgic Confession, article 22.
 Harold W. Hoehner, Ephesians: An Exegetical Commentary (Grand Rapids, MI: Baker Academic, 2002), ??. According to Obrien, several early commentators believed “faith” was the antecedent of “gift” (e.g. Augustine). Obrien notes, however, ““This interpretation is grammatically possible,615 assuming that the term denotes ‘faith’ and not Christ’s ‘faithfulness’, and it is consistent with Pauline teaching elsewhere (cf. Phil. 1:29). However, the context demands that this be understood of salvation by grace as a whole, including the faith (or faithfulness) through which it is received” (Peter Thomas O’Brien, The Letter to the Ephesians, The Pillar New Testament Commentary (Leicester: Apollos, 1999), 289.
 John Calvin, Institutes of the Christian Religion, trans. John T McNeill (Louisville, KY: Westminster John Knox Press, 2006), 541.
 See “Faith Defined,” Ligonier, (https://www.ligonier.org/learn/devotionals/faith-defined/).
 Peter van Mastricht, Theoretical-Practical Theology, ed. Joel R. Beeke, trans. Todd M. Rester, vol. 2 (Grand Rapids, MI: Reformation Heritage Books, 2018), 7.
 Ibid., 8.
 McGrath, Iustitia Dei, 206. It is important to note, however, that McGrath says “it is arguable that his translation of Paul’s term “justified” by the German phrase ‘gerecht werde (becomes righteous)’ rather than ‘gerechtfertigt’ is at least as significant, particularly given the trends towards declaratory approaches to justification which achieved dominance within Lutheranism during the 1530’s” (McGrath, 206–207). McGrath may be correct, yet the locus of the historical debate and the importance of his addition of “only” in Rom 3:18 is clear given the fact Trent addressed the issue and the historical debate that has ensued post-Reformation.
 Heiko Augustinus Oberman, Luther: Man between God and the Devil (New York, NY: Image Books, 1992).
 De Chirico, “Not by Faith Alone?”, 746.
 Ibid., 745–746.
 Calvin, Institutes, 748.
 Ibid., 749.
 Turretin, Justification, 86.
 Belgic Confession, 39.
 Horton, Justification, Vol. 2, 399.
 In advocating for justification sola fide, the Reformed tradition has also engaged with those who have argued that Reformed position inevitably leads to antinomianism. Roman Catholics leveled this charge and it has recurred for five-hundred years. Yet, for the Reformed, though justification is by grace alone through faith alone, that grace and faith are never alone.