When Paul was writing his letter to the Ephesians, the church was less than 30 years old. Many of the people who had walked and talked with Jesus were still around. James the brother of Jesus, who had become one of the leaders of the church, was executed by stoning in the same year that Paul wrote his letter. At least five of the apostles (Peter, John, Philip, Thomas and Simon) were still alive. Yet there was already disunity in the church. In chapter 4 of his letter to the Ephesians, Paul reveals his vision for unity of the church:
Do all that you can to maintain the unity of the Spirit in the bond of peace. There is one body and one Spirit, just as you were called to the one hope of your mission. There is one Lord, one faith, one baptism, and one God and Father of all, who is over all, and through all, and in all… He gave some apostles, some prophets, some evangelists, and some shepherds and teachers, to train the believers for the work of serving, for building up of the body of Christ, until we are united in the faith and in knowing the Son of God, fully mature, and completely Christ-like. We will no longer be children, tossed back and forth and carried about by every wind of opinion, by con-men, and by cunning and deceptive schemes.
Paul saw disunity as being caused by a lack of faith, of maturity, and of knowing the Son of God. His cure for disunity in the church was for the apostles, prophets, evangelists, shepherds and teachers to build up the body of Christ. A strong believer is one who has developed immunity to the wiles of religious con-men and to the latest fads and opinions that get blown around like the wind.