We little dream, sometimes, what a hasty word, a thoughtless speech, an imprudent act, or a confession of unbelief and fear may do to hinder our highest usefulness, or turn it aside from some great opportunity which God has been preparing for us.
Although the Holy Ghost uses weak men, He does not want them to be weak after He chooses and calls them. Although He uses the foolish things to confound the wise, He does not want us to be foolish after He comes to give us His wisdom and grace. He uses the foolishness of preaching, but, not necessarily, the foolishness of preachers. Like the electric current, which can supply the strength of a thousand men, it is necessary that it should have a proper conductor, and a very small wire is better than a very big rope.
God wants fit instruments for His power -- wills surrendered, hearts trusting, lives consistent, and lips obedient to His will; and then He can use the weakest weapons, and make them mighty through God to the pulling down of strongholds.