If a preacher’s behavior is consistent with his words, then his words will affect others. We know if a pure devotee preaches the glories of pure devotional service, his heart is free from envy and he is friendly to all living beings. He is thus always able to be absorbed in hearing spiritual subject matters and uses all of his time to glorify the Lord’s holy name and pastimes. When a devotee possesses such purity, his words will affect those who hear him and they too will strive for purity.
(SB 3.29.18, Krasnodar, June 1996)