As you may already realize, the Church of God is different from the churches of this world in many respects. Above all, it is governed by God through His Son, Jesus Christ, who is the Head of the Church (Colossians 1:18). On Earth, under Christ, are the human leaders He has chosen specially and put in office (Ephesians 4:11-13).
In other words, a man cannot choose the ministry of Jesus Christ for his vocation. Jesus said, “Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit” (John 15:16). It is Jesus Christ who selects those whom He will ordain into His ministry. His will in these matters is revealed through the established ministry.