The canonical books alone are the prophetic and apostolic writings.
But we do not doubt that the prophetic and apostolic writings are those which the church of God is accustomed, for that reason, to call by the name of the canonical books, because, knowing with certainty that these books are θεόπνευστος [God-breathed] (2 Tim. 3:16), she has always acknowledged them alone as canon of all Christian piety, according to which all religious controversy must be tried.
Girolamo Zanchi, Confession of the Christian Religion, §I.iii
Having confessed that the God who reveals has revealed himself to the prophets and apostles as well as to us through their Spirit-inspired writings (which are the “very word of God” [§I.ii]), Zanchi now has to say something about which writings are”canonical” and which aren’t.
God did not simply drop the Bible down from heaven. Instead, he chose to reveal himself through prophetic and apostolic authors. Zanchi doesn’t have much to say here about how God did this, since it wasn’t a matter of serious contention until later in church history.
What he does want to focus on is the the fundamental criterion for canonicity, which is that the books in question are theopneustos or God-breathed. If such God-breathed writings exist and if the church can recognize them as such, then they are the measuring stick (which is all that “canon” means) for “all Christian piety” and “religious controversy.” Not surprisingly, his next move in CCR will be to list all the books that the “whole church… acknowledges and embraces, without any doubt,… as most certainly the word of God” (§I.iv).
But where, you ask, does the church fit in? After all, Dan Brown convinced millions that church leaders gathered at the Council of Nicea chose which books got to be in the Bible. Fortunately, Zanchi never got around to reading The Da Vinci Code.
To be sure, CCR affirms that the church calls specific books canonical and other not, but it makes this distinction not because it claims a magisterial authority that binds (or looses) books to (or from) the canon. Rather, the church’s authority is ministerial. The church is accustomed to call Spirit-inspired books written by prophets and apostles canonical because (“for that reason”) they are theopneustos, which is to say “the very word of God” (as Zanchi put it §I.ii).
Needless to say—at least, I wish it were needless to say (but, things being as they are…)—this is not the same thing as saying that the church decides which books are the very words of God or that it confers an inspired status upon the Bible.
Books don’t gain or lose canonical status on account of the church’s recognition (even if the testimony of the church on their behalf may be important in convincing individuals to believe (as was famously the case for Augustine); they are canonical, so the church recognizes them.

Bruce Metzger comments:
Neither individuals nor councils created the canon; instead, they came to recognize and acknowledge the self-authenticating quality of these writings, which imposed themselves as canonical upon the church.
The New Testament, Its Background, Growth and Content, p. 318
William Barclay put it succinctly: “The New Testament books became canonical because no one could stop them doing so” (Making of the Bible, 78).
With that important clarification in mind, let’s take a moment to wonder at the fact that God gave the church the work of gathering together into a single volume the inspired writings that he chose to be included in the canon of Scripture. Like sheep that know the voice of their Shepherd, the Spirit-guided church recognized the voice of her God and responded. Because she hears that voice in books of the Bible, she recognizes them the canon, the ruler that measures theology, piety, and practice.
