What is expository preaching? What are the duties of the pastor and the role of the congregation?
Expositional preaching has three main characteristics. First, the passaged that is preached on is a single passage rather than various passages put together. Second, the main point or theme of the sermon is derived from the theme or main point of the passage. That is, expositional preaching seeks to exposit the text that is preached. Third, expositional preaching is typically lectio continua—that is, it is preaching that consecutively works through passages of Scripture in their biblical context.
Here are two of my favorite definitions:
“Expository preaching is that mode of Christian preaching that takes as its central purpose the presentation and application of the text of the Bible. All other concerns are subordinated to the central task of presenting the biblical text. As the Word of God, the text of Scripture has the right to establish both the substance and the structure of the sermon. Genuine exposition takes place when the preacher sets forth the meaning and message of the biblical text and makes clear how the Word of God establishes the identity and worldview of the church as the people of God” (R. Albert Mohler Jr., He is Not Silent: Preaching in a Post-Modern World, 65).
“To expound Scripture is to bring out of the text what is there and it expose it to view. The expositor pries open what appears to be closed, makes plain what is obscure, unravels what is knotted and unfolds what is tightly packed. The opposite of exposition is ‘imposition,’ which is to impose on the text what is not there. But the ‘text’ in question could be a verse, or a sentence, or even a single word. It could equally be a paragraph, or a chapter, or even a whole book. The size of the text is immaterial, so long as it is biblical. What matters is what we do with it. Whether long or short, our responsibility as expositors is to open it up in such a way that it speaks its message clearly, plainly, accurately, relevantly, without addition, subtraction or falsification” (John Stott, Between Two World, 125-26).
Thus, pastors have the duty to communicate God’s transforming truth, exalt Jesus Christ, teach the Bible so that people understand and apply what God has said, and encourage conformity to Christ (see e.g. Neh. 8:7-8; 1 Tim. 3:2).
The duty of the congregation is to attentively and prayerfully listen to and seek to apply the word taught with reverence and humility realizing that the pastor is seeking their welfare (Heb. 13:17) yet always being discerning to ensure that what is said is in accord with the word of God (Acts 17:11).
 Cf. Gospel Centered Youth Ministry, 55.
Worship must be carried out according to God’s revealed will. We want to worship God in the way that He has prescribed as best as we possibly can. So, we want our worship to be drenched in Bible. We want every aspect to pour out biblical truth.
Public worship must succeed as much as possible in carrying out what God has given us in His word to do. We should acknowledge, however, that “The New Testament does not provide us with officially sanctioned public ‘services’ so much as with examples of crucial elements.” Even though it is true that the New Testament does not give us “a complete manual of liturgics,” it does gives us clear things that we are to do.
The Great Commission in Matthew 28 tells us a few things that are essential for disciples of Jesus. Matthew 28:19-20 says: “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you.” We will look at implications from the Great Commission first and then turn to other crucial aspects of what it means to be the called out ones of God.
First, the church is given a command. Something we must collectively work at carrying out. We must make disciples and that includes sharing the good news of Jesus with others (Matt. 28:19-20; Acts 1:8). Public worship then is to facilitate discipleship (which includes encouraging evangelism).
Second, after those that we share Jesus with trust Him and repent of their sin then they are to be baptized (Matt. 28:19-20; Mk. 16:15-16). Thus, the church is to celebrate baptisms.
Third, we see the church must teach disciples to do all that Jesus the Lord commanded and so we see the importance of teaching, preaching, and reading Scripture within the church (Matt. 28:19-20). Why is preaching such a big deal? Preaching is essential because it teaches God’s truth so as to exalt Christ, encourage and build up, and exhort the gathered church.
Thus, we see the preaching of the Scriptures have a central place in the gathered services of the church. Sermons communicate God’s transforming truth, they exalt Jesus Christ, they teach the Bible so that people understand and apply what God has said, and they encourage conformity to Christ.
Fourth, gathering together on a regular basis is vital (Heb. 10:24-25). It was the practice of the early church to gather together on Sunday, the first day of the week, the Lord’s Day (Acts 20:7-11; 1 Cor. 16:2; Rev. 1:10). Thus, we see the vital importance of community.
Fifth, celebrating the Lord’s Supper together is essential because that’s what Jesus told us to do (1 Cor. 11:23-26). Jesus said “…do this…” so it’s not an option. We must gather together and celebrate the Lord’s Supper together.
Sixth, qualified leaders (elders/pastors) are very important so that they can ensure the health of the church. Titus 1:5-9 tells us that Paul put elders in Crete because things were out of order until qualified elders were leading. Leaders are also given to the church to teach and equip the saints for the work of the ministry (Eph. 4:11-14 see also Col. 1:28-29). Thus, it is important that qualified leaders have oversight of the public worship of the church.
Seventh, the Bible also tells us that it is important for churches to sing songs together. Ephesians 5 says, “Do not get drunk with wine, for that is debauchery, but be filled with the Spirit, addressing one another in psalms and hymns and spiritual songs, singing and making melody to the Lord with your heart, giving thanks always and for everything to God the Father in the name of our Lord Jesus Christ (vv. 18-20; cf. Acts 16:25; 1 Cor. 14:26; Col. 3:16). Notice too that it’s not just a person singing by their self but rather we address one another as we sing.
Eighth, it is also very important that churches be a holy witness and so church discipline is vital. See, for example, Matthew 18:15-20 (and also Phil. 2:15; 1 Cor. 5:9-12). Matthew 18:17 says, “If he refuses to listen to them, tell it to the church. And if he refuses to listen even to the church, let him be to you as a Gentile and a tax collector.” When the church gathers for public worship it is, as much as possible, to be a gathering of saints; or course, seekers are welcome to! But, false converts who will spread heresy like gangrene (2 Tim. 2:17) are not.
Ninth, another foundation of healthy public worship is the practice of spiritual gifts for the upbuilding of the body, the church (Rom. 12:4-8; 1 Cor. 14:26). This is important because “each is given the manifestation of the Spirit for the common good” (1 Cor. 12:7). It’s good to be “eager for manifestations of the Spirit” but we see from Scripture (and especially 1 Corinthians) that it’s more important that we “strive to excel in building up the church” (1 Cor. 14:12).
Tenth, from reading the New Testament we also see that prayer is an important part of the gathered church. Jesus taught on the importance of prayer and we can see from reading Acts that prayer was vital to the early church (e.g. Acts 1:14, 24; 2:42; 3:1; 4:23-31).
Eleventh, almsgiving and charity are also important aspects of a Christian church because Christians are called to care for and help people, as they are able. We see this seems to be the regular practice of the early church (e.g. Acts 6; 1 Cor. 16:1-4).
With all this being said, I agree with Michael A. Farley, we should not “read the NT in an inappropriately narrow and legalistic fashion as if the NT as a whole is to function as a collective new covenant version of Leviticus. If none of the individual NT books were written to be an exhaustive liturgical manual, then it is wrong to read and apply the NT as a whole in this restrictive fashion.”
 I appreciate what Michael A. Farley says: “Evangelical scholars employ a range of very different hermeneutical strategies in applying the Bible to worship. This is not surprising, of course, since evangelicals are divided over the theory and practice of biblical hermeneutics in many areas of theology. The first step toward progress in reconciling divergent views is a clear recognition and accurate characterization of the diversity of hermeneutical approaches to constructing a biblical theology of worship. If discussion can take place at this level, evangelicals can avoid the frustrating experience of talking past one another without comprehending why one’s arguments are not persuasive to one’s interlocutors” (“What Is “Biblical’ Worship? Biblical Hermeneutics and Evangelical Theologies of Worship,” JETS 51/3 : 610).
 Worship by the Book, 52.
 Farley, “What Is “Biblical’ Worship?,” 610. “There is no single passage in the New Testament that establishes a paradigm for corporate worship” (Worship by the Book, 55).
 For example, I really appreciate this summary by Edmond Clowney: “The New Testament indicates, by precept and example, what elements of [corporate] worship are. As in the synagogue, corporate prayer is offered (Acts 2:42; 1 Tim. 2:1; 1 Cor. 14:16); Scripture is read (1 Tim. 4:13; 1 Th. 5:27; 2 Th. 3:14; Col. 4:15, 16; 2 Pet. 3:15, 16) and expounded in preaching (1 Tim. 4:13; cf. Lk. 4:20; 2 Tim. 3:15-17; 4:2). There is a direct shift from the synagogue to the gathering of the church (Acts 18:7, 11; cf. 19:8-10). The teaching of the word is also linked with table fellowship (Acts 2:42; 20:7, cf. vv. 20, 25, 28). The songs of the new covenant people both praise God and encourage one another (Eph. 5:19; Col. 3:15; 1 Cor. 14:15, 26; cf. 1 Tim. 3:16; Rev. 5:9-13; 11:17f; 15:3, 4). Giving to the poor is recognized as a spiritual service to God and a Christian form of ‘sacrifice’ (2 Cor. 9:11-15; Phil. 4:18; Heb. 13:16). The reception and distribution of gifts is related to the office of the deacon (Acts 6:1-6; Rom. 12:8, 13; cf. Rom. 16:1, 2; 2 Cor. 8:19-21; Acts 20:4; 1 Cor. 16:1-4) and to the gathering of believers (Acts 2:42; 5:2; 1 Cor. 16:2). The faith is also publically confessed (1 Tim. 6:12; 1 Pet. 3:21; Heb. 13:15; cf. 1 Cor. 15:1-3). The people receive God’s blessing (2 Cor. 13:14; Lk. 24:50; cf. Num. 6:22-27). The holy kiss of salutation is also commanded (Rom. 16:16; 1 Cor. 16:20; 2 Cor. 13:12; 1 Th. 5:26; 1 Pet. 5:14). The people respond to praise and prayer with the saying of ‘Amen’ (1 Cor. 14:16; Rev. 5:14; cf. Rom. 1:25; 9:5; Eph. 3:21 etc.). The sacrament of baptism and the Lord’s Supper are explicitly provided for. Confession is linked with baptism (1 Pet. 3:21); and a prayer of thanksgiving with the breaking of bread (1 Cor. 11:24)” (Clowney, “Presbyterian Worship,” Worship: Adoration and Action, ed. D.A. Carson, 117 as quoted in Worship by the Book, 48).
 Westminster Confession of Faith, ch. 1
 Farley, “What Is “Biblical’ Worship? Biblical Hermeneutics and Evangelical Theologies of Worship,” JETS 51/3 (2008): 610-11. “Liturgical theology ought to be a matter of wisdom that results from reflection upon all that God has revealed in Scripture about corporate worship in light of the person and work of Christ. Thus Christians need to employ a more theologically oriented regulative principle rather than one that would limit legitimate liturgical practices solely to those explicitly attested in the NT” (Farley, “What Is “Biblical’ Worship?,” 611). In a similar way, John Piper says, “In the Old Testament, there is an extremely detailed set of guidelines for how everything should be done in relationship to the tabernacle and the sacrifices and the way people come to God. In the New Testament, those details are almost completely lacking. I am tempted to say completely lacking. There is no way anybody could construct a normative worship service from what we have in the New Testament. Lots of people think they can, but I don’t think so. There is more tradition going on there than they realize.” “Do We Really Need Musical Worship?” https://www.desiringgod.org/interviews/do-we-really-need-musical-worship. John Piper goes on to say, “I don’t think you look for prescribed patterns in the New Testament. You look for emphases, trajectories, implications, the nature of God, the nature of man, the nature of his mind, the nature of his emotions, the nature of salvation, the nature of gifts. And what you find is that there is an extraordinary centrality and emphasis to the word of God in the Christian life” (Ibid.).
Why are sermons such a big deal? The Bible tells us to sing as the gathered church. The Bible also tells us to celebrate the Lord’s Supper and baptisms. But why are sermons essential?
Sermons are essential because they teach God’s truth so as to exalt Christ, encourage and build up, and exhort the gathered church.
First, the teaching aspect of the sermon is important. Its importance is seen all over Scripture (e.g. Neh. 8:7-8; 1 Tim. 3:2). God has spoken and so helping people understand and apply the revelation from Him is life-changing. God’s people, however, are able to understand His truth. This is because all believers are indwelt by the Holy Spirit (Eph. 2:22; 1 Cor. 3:16; 2 Cor. 6:16), Jesus has made all those in Him priests (1 Pet. 2:5, 9; Rev. 1:5-6), and Scripture is clear on the things which are “necessary to be known, believed, and observed, for salvation” (The Westminster Confession of Faith, ch. 1). Qualified teachers are still vital, however, because sound (or healthy) doctrine is vital. That is, in part, why pastors must be “able to teach” (1 Tim. 3:2; 2 Tim. 2:24) and defend the truth (2 Tim. 2:25; Titus 1:9). We also see in Scripture that right teaching leads to maturity and the body of Christ being equipped for every good work. Believers may be able to subsist on milk but teachers are able to provide needed meat (2 Cor. 3:2; Heb. 5:12-13).
Second, communicating God’s truth in sermons is vital because the Bible is the authoritative word of God and it is uniquely profitable (2 Tim. 3:16-17). It is our sole authority for faith and practice. Scripture is a light (Ps. 119:105,130), a sword (Eph. 6:17), a hammer (Jer. 23:29), and a surgeon (Heb. 4:12). Scripture is more essential than bread (Matt. 4:4), better than gold (Ps. 19:10; 119:72), and we need it to live (Ps. 119:144). Scripture is perfect (Ps. 19:7), true (Ps. 19:9), pure (Ps. 19:8), and eternal (1 Pet. 1:25). Scripture contains the words of life (Jn. 6:68) and the words that are breathed out by God (2 Tim. 3:16). Scripture gives joy (Ps. 119:111; Jer. 15:16), makes wise (Ps. 19:7), equips (2 Tim. 3:17), guards (Ps. 119:9), guides (Ps. 73:24; 119:105), saves (1 Pet. 1:23), sanctifies (Ps. 119:9,11; Jn. 17:17), and satisfies because by it we know God (1 Pet. 2:3 cf. Ps. 16:11; Jn. 17:3).