Q. What is true faith?
A. True faith is not only a sure knowledge by which I hold as true all that God has revealed to us in Scripture; it is also a wholehearted trust, which the Holy Spirit creates in me by the gospel, that God has freely granted, not only to others but to me also, forgiveness of sins, eternal righteousness, and salvation. These are gifts of sheer grace, granted solely by Christ’s merit.
—Heidelberg Catechism, Q&A 21