“Be well instructed in theology, and do not regard the sneers of those who rail at it because they are ignorant of it.  Many preachers are not theologians, and hence the mistakes which they make.  It cannot do any hurt to the most lively evangelist to be also a sound theologian, and it may often be the means of saving him from gross blunders.  Nowadays, we hear men tear a single sentence of Scripture from its connection, and cry, ‘Eureka! Eureka!’ as if they had found a new truth; and yet they have not discovered a diamond, but only a piece of broken glass.  Had they been able to compare spiritual things with spiritual, had they understood the analogy of the faith, and had they been acquainted with the holy learning of the great Bible students of past ages, they would not have been quite so fast in vaunting their marvelous knowledge.

“Let us be thoroughly well acquainted with the great doctrines of the Word of God, and let us be mighty in expounding the Scriptures.  I am sure that no preaching will last so long, or build up the church so well, as the expository.  To renounce altogether the hortatory [giving exhortation] discourse for the expository, would be running to a preposterous extreme; but I cannot too earnestly assure you that, if your ministries are to be lastingly useful, you must be expositors.  For this purpose, you must understand the Word yourselves, and be able so to comment upon it that the people may be built up by the Word.  Be masters of your Bibles, brethren; whatever others works you have not searched, be at home with the writings of the prophets and apostles.  ‘Let the word of God dwell in you richly.’”

— Charles H. Spurgeon, An All Round Ministry (c. 1870s)