Gerhard and Walther

For such a faith is not an ordinary scientific knowledge, much less a worthless, perishable boast of the mouth. Instead it is a living, powerful assurance, a change of the heart—indeed, of the entire person. It is a living, active, mighty thing, for true faith is active in love, and manifests itself through works.—Johann Gerhard, Schola Pietatis I:120

The Church reveals and proves herself faithful by this alone: she is subject to Christ, who rules her with His Word as the scepter of His eternal love. Every word of Christ is a commandment for her that she carries out with joy, even if it costs her blood and life.—C. F. W. Walther, God Grant It!, p. 136.