'Preaching' in the Bible

For since, in the wisdom of God, the world by wisdom has not known God, God has been pleased by the foolishness of the preaching to save those that believe.

and my word and my preaching, not in persuasive words of wisdom, but in demonstration of the Spirit and of power;

but if Christ is not raised, then, indeed, vain also is our preaching, and vain also your faith.