"The truth is, no preaching ever had any strong power that was not the preaching of doctrine. The preachers that have moved and held men have always preached doctrine. No exhortation to a good life that does not put behind it some truth as deep as eternity can seize and hold the conscience. Preach doctrine, preach all the doctrine that you know, and learn forever more and more; but preach it always, not that men may believe it, but that they may be saved by believing it."