So what is "ministry"? While every Christian has a role of service within the body and extending to the world at large, historically we have referred to "the ministry" as service within the Church as a pastor, priest, or sometimes a monk of some sort. So we'll continue to use that handy label. I won't say that someone with a "ministry of airplane mechanic" isn't serving his neighbor for Christ. I'll just say that I'd rather call that his vocation and rejoice that he does it well.
Schone observes that the ministry is a divine institution. Christ gives this ministry to the church, linking it to the original apostles who designate other people whom they consider Christ is calling. Christ himself is the Lord of the ministry. His servants do not get to choose what to do or say. They only work within the bounds he has established. And the ministry is always related inextricably with the church. It would not exist without the supernaturally created institution of the Church. We remember that the Church is not a human gathering. It is a gathering of humans called and assembled by the Holy Spirit. It is not of our own choice any more than salvation is of our choice.
The ministry, like any other subgroup of the Church, is something with a distinctive role. This does not indicate superiority or inferiority within the body. It is simply a designated role that Christ has given some people and not others. Ministers historically, ever since the New Testament, have been recognized and ordained in a particular way so others will know who is serving in this role. This idea has been eroded, particularly in American Christianity over the past 200 years or so, as people have engaged in self-ordination and have taken on roles which may not have been given them following a biblical pattern.
What are ministers to do? Obviously, they are called to proclaim the Gospel and administer the sacraments. They have also been given the responsibility of hearing confession and proclaiming absolution (John 20.21-23), judging doctrine as scholars of theology, acting as the executive in cases of excommunication, presiding over churches, ordaining other ministers, and leading in missionary activity.
This is a busy life! There are some responsibilities a minister has which may make many people cringe. In fact, they should make the minister cringe. I have noticed in the last few years that whenever I am selected to preach in a church, though I look forward to it because I love proclaiming God's Word, I am fearful because I have it in my power to lead people astray and run afoul of sound doctrine. It's quite a burden to guide people well, to serve as a good shepherd for believers' souls.
May the Lord bless those who are ministering among us!