Tony Merida, Teaching Pastor of Temple Baptist Church, Hattiesburg, MS wrote Faithful Preaching, 2009. In this book, he gives the benefit of a pastor doing expository preaching. Let me list his nine benefits with his explanations as they appear in the book:
First, exposition calls for attention to be given to biblical doctrine. One has to preach on every doctrinal issue if they preach the whole council of God. This keeps the preacher from only dealing with his favorite subjects, and it will give the hearers theological stability.
Second, exposition, done well, is good for both audiences: believers and non-believers. If one preaches the Scriptures in view of its redemptive history that culminates in Jesus, then the gospel will be integrated naturally into every sermon. The unbeliever will be confronted with his need for repentance and his hope that is in Christ. On the other hand, exposition will grow the believers in the church and remind them that they do not work for grace but from grace and by grace. So I am a huge fan, and hopefully a practitioner of, gospel-filled exposition.
Third, exposition gives authority to the message. Preachers that just try to be cutting-edge, or fill their sermons with endless stories, lose authority. The authority of the sermon is not in the suggestions, stories, or observations of the preacher. Authority comes from God’s Word.
Fourth, exposition magnifies Scripture. Preachers may claim to believe in the sufficiency of God’s Word, but if they do not take people for a swim in the text, then they deny their belief in practice. You will show your people what you believe about the Bible by how you use it. This is how you magnify the nature of Scripture with something more than repeated clichés.
Fifth, exposition is God-centered not man-centered. By starting with God’s Word instead of a popular idea or a perceived need, the preacher will expose the nature and truth of the Triune God to people—which is their greatest need.
Sixth, exposition provides a wealth of material for preaching. By moving through the Scriptures, you will avoid reductionism; that is, picking only the topics that seem important (money, sex, and power). The Bible will provide you with more subjects to preach on than you ever dreamed. A holistic approach will produce holistic Christians.
Seventh, exposition grows the person delivering the Word. This is the most enjoyable part of committing to exposition. By studying the text week by week, you will be developed as a disciple and you will continue to fill your soul with spiritual nourishment.
Eighth, exposition ensures the highest level of biblical knowledge for the congregation. By regularly expounding the Word of God, you will train a group of people who know the Scriptures. Further, you will not only remind them of who they are in Christ and how to glorify God, but you will also train them to think Christianly. Other types of preaching may put a band aid on people’s felt needs, but such will not transform their worldview unless they understand the mind of the Holy Spirit in the Word. Exposition is a primary means of transforming people by the renewal of their mind (Rom 12:2).
Finally, exposition teaches people how to study the Bible on their own. The old saying is true, “Give a man a fish and you will feed him for a day; teach him how to fish and you will feed him for a lifetime.” By moving systematically through passages and books you will teach the people how to engage the text. They will understand the importance of context, words, and biblical genres. After doing exposition in various places, I have discovered that the people are able to predict my next point, and see how I got it. Expository preaching will produce expository preachers and expository students.