Here is Baptist theologian John Gill on the necessity of pastors to communicate the Scriptures well:

He must not only be able to teach, but he must be “apt to teach;” which aptitude lies in a good degree of elocution, and a free utterance of speech; for it is of little avail what is a man’s capacity, what the thoughts of his mind, and what stock of knowledge he has, unless he can clothe his ideas with proper words to convey the understanding of them to others; the royal preacher “sought to find out acceptable words;” such as were suitable to express his meaning, and to give delight and pleasure, as well as yield profit to them that heard him; and especially the taught words of the Holy Ghost are to be made use of. Apollos was an eloquent man, and mighty in the scriptures, well versed in them, and which greatly improved his gift of elocution; a good textuary makes a good preacher; a free and ready utterance is necessary; such an one is like the scribe and householder (Matthew 13:52). The apostle Paul himself desired the Ephesians to pray for him, “that utterance might be given him,” (Eph. 6:19)