The Church Has No Word of Its Own

Quoting Francis Pieper in Christian Dogmatics, Vol. 1, p. 315:

What the Church proclaims (the "Word of the Church") also has divine power and efficacy, but always only in so far as the Church remains true to its commission and proclaims only God’s Word (Matt. 28:19; Rom. 3:2; 1 Tim. 6:3 ff.; 2 John 9-10). The Church has no word of its own. Whatever is not taken from Scripture is not the "Word of the Church," but what Luther bluntly calls "prattle." Also other books can exert a divine power and efficacy, but always only inasmuch as they have absorbed God’s Word.