First and foremost, as Colossians 1:18 indicates, God governs the Church of God, through His Son, Jesus Christ, who is the Head of the Church.
As for the humans that Christ puts in positions of leadership in His Church, He says in John 15:16, “You have not chosen Me, but I have chosen you, and ordained you, that you should go and bring forth fruit…” God chooses His ministers. They do not decide that they “have a calling” and choose themselves.
Service and good works largely fulfill the responsibility of a minister. In I Timothy 3:1, Paul says, “This is a true saying, if a man desire the office of a bishop (i.e. pastor), he desires a good work.” Paul then continued in verses 2 through 7 to outline some of the prerequisites to serving as a minister.
An important criterion is that the man is not “newly come to the faith” (vs. 6). A potential minister then must have first served for some time as a member of the Church, growing and bearing “fruit” (Matt. 7:16; Gal. 5:22-23). In such matters, Christ will reveal His will through the established ministry. And, as Christ did with the disciples, ordination follows only after a period of training and preparation.
Therefore, The Restored Church of God ordains only baptized, spiritually mature members whom God is calling into His ministry. Paul explains the purpose of the ministry in Eph. 4:11-13, and James warns of a “greater condemnation” (i.e. judgment) for those with a higher office (James 3:1).
Any member of the Church can, of course, serve without being ordained. In fact, it is his Christian duty! (See James 1:27 and Matt. 25:35-36.)
For more details on how God’s government works, you may wish to read the following literature: