This study is based upon the New City Catechism.
So then it depends not on human will or exertion, but on God, who has mercy. (Romans 9:16)
God justifies His people by imputation, not by infusion, of righteousness. Concerning the man who stands guilty before God, justification is appropriated by faith and nothing else. We are justified by faith alone. However, we know that faith is never alone. Saving faith is always accompanied by good works. This is the rich theological heritage handed down by Paul and James, who, rather than contradict one another, actually serve as complementary theologians on Sola Fide. As the Westminster Confession of Faith explains, “Faith, thus receiving and resting on Christ and his righteousness, is the alone instrument of justification; 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” (11.2).
This concept of justification (imputed righteousness through faith alone) has rightly divided Protestants and Roman Catholics for centuries. Unity was worked-out between Roman theologians and magisterial Reformers, on nearly every point except the word “imputation.” Luther took his principle stand there with “alien” righteousness, “the righteousness of another, instilled from without. This is the righteousness of Christ by which he justifies through faith.”
This was the calling-card of the Reformation, but another doctrinal divide was manifestly more fundamental. From where does saving faith originate? What creates saving faith? Most students of Scripture acknowledge only two options: God or man. There is no debate concerning our need of grace. The disagreement arises when we ask, “Who has the deciding decision in salvation: God or man? Whose will is the lynch-pin?” Responding to Erasmus, Luther claimed that this question was the hinge upon which the Reformation turned.
We make no hesitation in answering, “It depends not on human will or exertion, but on God, who has mercy” (Romans 9:16). The purview of this statement is redemption, with broad consequences stemming from singular lives (vv.6-13). “He has mercy on whomever he wills, and he hardens whomever he wills” (v.18). God’s will, not man’s, is the lynch-pin of salvation. We are born dead in trespasses and sins (Ephesians 2:1), as unable to respond positively to God (Romans 8:1-8) as Lazarus was unable to respond to his funeral mourners (John 11:1-37). There was One voice he did respond to, however, because it was an authoritative voice. That is to say, the voice of One Who commands the universe (Matthew 8:27; Hebrews 1:3). “Lazarus, come out,” Jesus called, and “the man who had died came out” (John 11:43-44). Similarly, our will is dead and unable to respond to the Gospel until the Spirit effectually calls us from death to life (3:1-15). Everyone who receives this secret, inward call is saved: “Those whom he called he also justified” (Romans 8:30). This is not a call that looks for differences (like an invitation), but a call that creates differences: “Though they were not yet born and had done nothing either good or bad – in order that God’s purpose of election might continue, not because of works but because of him who calls – she was told, ‘The older will serve the younger’” (9:11-12).
Therefore, we give a hearty “Amen” to the confession, which defines the effectual call of God upon His elect as being “out of that state of sin and death in which they are by nature, to grace and salvation by Jesus Christ; enlightening their minds spiritually and savingly to understand the things of God; taking away their heart of stone, and giving unto them an heart of flesh; renewing their wills, and by his almighty power determining them to that which is good, and effectually drawing them to Jesus Christ; yet so as they come most freely, being made willing by his grace” (WCF 10.1). From where does faith come? It comes from the Holy Spirit. There is no fountain of morality whelming up inside our souls, apart from the grace of God in us, and so there certainly is no hope for saving faith without the regenerating, powerful call of the Spirit. “Everyone who believes that Jesus is the Christ has been born of God” (1 John 5:1).
Question: Since we are redeemed by grace alone, through faith alone, where does this faith come from?
Answer: From the Holy Spirit.
 Sproul, Are We Together? (Reformation Trust Publishing; Stanford, 2012), 42.
 Luther in “Two Kinds of Righteousness” preached 1519, referenced in Dillenberger’s Martin Luther: Selections from his writings (Anchor Books; Garden City, 1961), 86.
 Dillenberger, 179.