Six hundred years ago, Jan Hus wrote that “neither is the pope the head nor are the cardinals the whole body of the holy, universal, catholic church. For Christ alone is the head of that church, and his predestinate are the body and each one is a member, because his bride is one person with Jesus Christ” [The Church, ed. David S. Schaff (Charles Scribner’s Sons, 1915), 66.]. One hundred years later, Luther echoed those words. That Reformation tradition was carried forward by the Puritans. Leland Ryken writes:

   The greatest of all Puritan legacies in regard to ecclesiastical theory was also the most revolutionary in its time. It was the notion that the church is a spiritual reality. It is not impressive buildings or fancy clerical vestments. It is instead the company of the redeemed.
   The Puritans repeatedly showed their acceptance of Luther’s dictum that “The church is a spiritual assembly of souls. . . . The true, real, right, essential church is a matter of the spirit and not of anything external.” For William Gouge the church consists of those who “inwardly and effectively by the spirit . . . believe in Christ.’’ John Hooper denied that the church consists of “bishops, priests and such other,” affirming rather that it is “the company of all men hearing God’s Word and obeying unto the same.” Richard Baxter agreed: the church is “a holy Christian society for ordinary holy communion and mutual help in God’s public worship and holy living.”
   Implicit in these definitions of the church is a Puritan preference for the invisible church over a type of institutional structure. The church is emphatically not the professional clergy and their rituals. “What understand you by the church?” asked John Ball’s Catechism. The answer: “by the church, we understand not the pope. . . ; nor his bishops and cardinals met in general council. . . ; but the whole company of believers.” If the church is essentially invisible rather than institutional, its head is obviously not a pope or church council, but Christ. The Puritans reiterated this again and again, as when Gouge spoke of “that church whereof Christ is properly head.”

—Leland Ryken, Worldly Saints: The Puritans as They Really Were (Academie Books, 1986), 115.