The Ephesians are fellow citizens, part of God's family, and building blocks of the temple of God. This temple exists for His purposes. The whole book has been leading up to this section. There will be a switch in the next chapter that expands the understanding of what is being discussed here. Paul continues to described how the Ephesian Christians are part of the body of Christ/family of God. Ending with becoming a dwelling of God in the Spirit. He is emphasizing that they are part of God's plan and purpose.
God through Christ has brought us together so that there is no redemptive difference among those in the kingdom. There will always be an understanding that we come from different experiences, but we are unified and equal before God Because of Christ.
They are not strangers or aliens. They are fellow citizens (19). In the last sections we have been told: we all have the same sin issues (3), we are made alive in Christ (5), we are raised with Him (6), we are saved by grace(8), we are created to work (10), He is our peace (14), we are brought together (17), and NOW we are no longer Strangers and Aliens (19). Paul is explaining how the things he has been telling the Ephesians works toward unity. Paul tells them that they are an equal part of the kingdom with any Jewish Christian.
The church is built on the foundation of the apostles and prophets, Jesus, the corner stone (20). The Corner stone is the first stone laid in a foundation. It is the most planned placement. Everything else is gauged by this stone. Jesus was the planned part, before the foundation of the world. The apostles and prophets (old and new testament) are the foundation for the teaching/ministry of the church. The church brings the two groups into one new man. The apostles and prophets according to FF Bruce, "These two offices are the foundational ministries in the church..." (304).
The union that the two groups now enjoy is based solely on Christ. He provides the means of unity. The foundation of the church is not men or offices, but on doctrine and orthodoxy. When apostles and prophets are mentioned as foundational, it is not the people, but what the people taught that provides the foundation. Everyday God is adding to the building/body. We are put into Christ, each of us has a place and mission. This fitting together brings to mind the idea of being parts of Christ's body as in I Corinthians. We are individually part of Jesus' body. We are fitted together. Like a building being built by specialized contractor who knows exact ally what is needed for the building to accomplish its purpose. So the Body of Christ is being built by an expert Who knows what is needed for fulfilling the purpose of the church.
We are growing into a holy temple of God in the Spirit (21-22). There is a place for everyone in the Temple of God. Everyone is a part of the Temple and has a specific task or tasks. This building is growing into a holy place. A place of worship to God in the Spirit! Obviously the building is a metaphor for the body of Christ. We are part of the temple that is growing in holiness and openness to God's Spirit.
The applications for this section are limitless. First, we are one in Christ - there is no us versus them in the body. That type of thinking within the body is divisive. We unite on the doctrines of Christ/God, and allow for freedom in non-essential areas. Second, the church is built on Jesus Christ and the doctrine of Christ as taught in the Scriptures. We must rely on the teaching of the Bible to under-gird our efforts for the Kingdom/Body. Third, the healthy direction for a church is being fit together and growing. The church is not healthy if it is not growing into "a dwelling of God in the Spirit." Every church should be a growing as a unified body of believers that is built on Jesus Christ and His doctrine.
