What is the theological study of ecclesiology?

from the old testament

• The Old Testament does not explicitly teach about ecclesiology—the theological study of the church—because the church, as the body of Christ, is a New Testament reality. However, the Old Testament provides foundational concepts that help us understand the church theologically. Israel was called to be God’s holy people, set apart for worship and obedience (Exodus 19:5-6; Deuteronomy 7:6). The church does not replace Israel, but Israel shows that God has intentions for faith-based community.
• The Old Testament outlines roles like priests, Levites, judges, and prophets (Exodus 28; Numbers 3), showing God’s design for organized spiritual leadership and teaching within His people. This provides a pattern for understanding spiritual authority and order in the church.

from the new testament

• The study of the church begins where the church began, at Pentecost, when the Holy Spirit came upon the disciples and united them into one body (Acts 2:1-4, 41). It then shows that Christ has continued to build His church, just as He promised (Matthew 16:18), and that it endures because Jesus is its head and sustainer, working through His Spirit to bring people to faith and to preserve them in the truth (Ephesians 1:22-23; Colossians 1:18).
• Ecclesiology also studies both the universal church—all believers united to Christ across time and place—and the local church, where those believers gather for worship, fellowship, teaching, and prayer (Acts 2:42-47; Hebrews 10:24-25). Each local church is an expression of the larger body of Christ and participates in His ongoing work in the world.
• Additionally, it explains the mission of the church as flowing directly from Christ’s command to make disciples, baptize, and teach all nations (Matthew 28:19-20; Acts 1:8). This calling undergirds every aspect of church life and ensures that the gospel remains central to its worship, ministry, and service.
• Ecclesiology also examines the two ordinances given by Christ—baptism and the Lord’s Supper. Baptism publicly identifies believers with Christ’s death and resurrection (Romans 6:3-4; Acts 2:41), while Communion proclaims His death until He returns (1 Corinthians 11:23-26). Both ordinances express unity in Christ and serve as visible signs of the gospel.
• Through it, we also learn that the New Testament outlines clear leadership and order for the church. Elders (or pastors) are called to shepherd and teach, while deacons serve in practical ministry to support the congregation’s needs (Philippians 1:1; 1 Timothy 3:1-13; Titus 1:5-9). These roles exist to maintain doctrinal integrity, spiritual health, and faithful service among God’s people.
• Finally, it shows us that the church is described as one body made up of many members, each gifted by the Spirit for the good of all (Romans 12:4-8; 1 Corinthians 12:12-27). No believer is unnecessary; every member contributes to the church’s growth and maturity. Ecclesiology, therefore, reminds us that the church is not merely an organization but a living organism—Christ’s body on earth, empowered by His Spirit to glorify Him and serve His mission.

implications for today

Understanding the church is essential for understanding our relationship to Christ. Scripture describes believers collectively as His body, with Christ as the head. The church, then, is not a place but a community of redeemed people joined together by faith in Him. Seeing the church this way changes how we think about worship and belonging. We gather not simply to attend a service, but to share in the life of Christ with other believers.

This also helps clarify what the church does when it gathers versus when it scatters. When the church scatters into the world, believers carry the gospel to the lost through evangelism. When it gathers, the focus shifts to the growth and maturity of those who already believe. The gathered church exists to worship, pray, learn, and encourage one another so that each member is strengthened for faithful living and witness. A proper understanding of the church protects us from viewing it as optional or merely evangelistic. Instead, we see it as God’s means for building up His people and displaying His glory until Christ returns.