Composing a doctrinal statement (or any other essential documents) can be one of the most arduous (but crucial) projects undertaken by a church. In this series, I’m sharing my own doctrinal statement, a section at a time, in an attempt to provide a helpful example of a detailed statement that is worded positively, but articulated precisely enough to exclude certain theological positions for the protection and unity of the church.
Section 7 — The Church
We believe that God’s plan for this dispensation is that the people of God regularly assemble and associate themselves in local communities by establishing churches under the authority of God’s Word and for the purpose of edifying and equipping disciples of Christ to better know Him, love Him, live in obedience to Him, and disciple others toward a deeper relationship with Him.
A church is a local congregation of Christians who, by mutual commitment, regularly assemble together in Christ’s name to declare, uphold, and proclaim the Word and worth of God, and to officially affirm, equip, and oversee one another’s faith in Christ through discipleship, corporate worship, the teaching and preaching of God’s Word, and the observance of the ordinances. 
The church is governed by the teachings of God’s Word through delegated leadership, and is to obey Christ’s commission to make disciples  by evangelizing the lost, and training, equipping, and developing believers to better know Christ, become more like Him, live in obedience to Him, and be used by Him for His glory.
Membership: We believe that every believer should formally identify with the believing community by becoming a member of a local church . Church membership is a formal relationship between a local church and a Christian characterized by the church’s affirmation and oversight of a Christian’s discipleship, and the Christian’s submission to living out his or her discipleship under the authority and in the care of that church .
Leadership: We believe that the one, supreme authority for the church is Christ, and that church leadership, order, discipline, and worship are all appointed through His sovereignty as found in the Scriptures. We believe that Jesus authorized the local assembly to exercise the authority of the keys of the kingdom . The church is to exercise this authority under the oversight and leadership of biblically qualified elders (also called pastors and overseers). The congregation is to be led by elders and served by deacons, whose qualifications and duties are defined in the New Testament. Though the church utilizes these two offices, all believers have equal access to God and are gifted and called to serve Him as ministers. We believe that the elders lead as servants of Christ and are commissioned by Him to bear the responsibility of teaching, leading, protecting, and caring for the local church. The church’s leaders are to model the servant-leadership of Jesus Christ. The congregation is to recognize, support, and submit to their leadership within scriptural guidelines.
Universal Church: The family of God as it exists in this dispensation, the worldwide New Covenant community, is often collectively called the Church  — made up of all who have been redeemed by God since the cross of Christ, both Jew and Gentile. 
(Matthew 16:15–19; 18:15–20; 28:19–20; Acts 2:37–47; 14:23, 27; 15:13–21; 20:17–28; 1 Corinthians 5:9–13; 11:17–34; 12:12–27; 14:12, 26; 2 Corinthians 2:6; 5:14–21; Galatians 1:6–9; Ephesians 1:22–23; 3:1–6, 21; 4:11–16; Philippians 1:1; Colossians 1:13, 18; 1 Thessalonians 5:12; 1 Timothy 2:12; 3:1–15; 5:3–9, 17–22; 2 Timothy 2:2, 15; 3:16–17; 4:3; Titus 1:5–9; Hebrews 10:22–25; 13:7, 17; 1 Peter 5:1–5; 1 John 1:3)
1) For an explanation and discussion of my definition of the local church, go to this post.
2) For a study in biblical discipleship, see: Defining Discipleship; Knowing vs. Loving Christ; The Requirement of a Disciple; The Commission and Means of Disciple-Making; and The Resemblance and Mark of a Disciple
3) Jonathan Leeman is probably the go-to resource on church membership. I suggest this, this, and this. Also, Grace to You has some helpful posts here, here, here, here, and here.
4) What is Church Membership? (Leeman); The Church and the Surprising Offense of God’s Love: Reintroducing the Doctrines of Church Membership and Discipline (Leeman)
5) Understanding the Congregation’s Authority (Leeman); Don’t Fire Your Church Members (Leeman)
6) For a study of the ekklesia (church; assembly) in the New Testament, see here.
7) Every doctrinal statement I have ever seen places the universal church first, and the local church second. Doctrinal statements usually launch into an in-depth discussion of the concept of the universal church (which, frankly, is not an overly helpful or productive concept exegetically or hermeneutically), and then have a brief statement tagged on the end about how “the local/physical expression of this universal body is in the establishment of local churches.” These doctrinal statements reflect the common attitude of evangelicalism today, which unabashedly places priority on the universal church, while devaluing the local church to nigh nonexistence. I do not believe this is the biblical viewpoint. Scripture has so much more to say about the local church than it does about the universal church. (And, functionally, the local church is the only assembly that actually regularly assembles). In fact, I would say that, ontologically, the local church actually has precedence and primacy, and the universal church exists only as a derivative category that conceptually engulfs all believers around the world and throughout time. I suppose I need to write a paper on this sometime — I know this is an uncommon and unpopular viewpoint — but regardless, that is why I place the local church first here.