Karl Barth on preaching

"Homiletical theory largely followed Augustine's lead until Karl Barth. ... Barth's homiletical starting point is God: 'Preaching is the Word of God which he himself has spoken'. God chooses to use human words but is never bound by human words. ... The preacher must not, however, become arrogant, for preaching depends always on God and is possible only by God's power. 'Revelation is a closed system in which God is the subject, the object, and the middle term'. In preaching, 'God alone must speak'. Preaching is not a forum for human thoughts, ideas, reflections, or the propagation of ideologies."

(Andre Resner, Preacher and the Cross, Eerdmans, 1999, pp58-59)