My Guru Maharaja used to say, prana ache yara sei hetu pracara. A person can become a preacher if he has got life. A dead man cannot become a preacher. So you must be very enthusiastic that "I shall preach the glories of the Lord to my best capacity." It is not that one has to become very learned scholar to become a preacher. Simply it requires enthusiasm, "My Lord is so great, so kind, so beautiful, so wonderful. So I must speak something about my Lord." This is the qualification, enthusiasm.

>>> Ref. VedaBase => The Nectar of Devotion — Vrndavana, October 20, 1972