In my previous background, it is common to hear that they have become ministers/pastors , because just like the prophets of old who received a visitation from God, the same has happened to them. In the same way that they can identify a conversion experience, they can identify a calling experience too, i.e. that particular time when they heard an audible voice telling them to become a minister.
In my early years as a Protestant Christian, I could identify some such subjective experience. However, after that, I struggled. I struggled because I have encountered ministers who had no doubts as to validity of their calling experience yet, I doubted mine. So eventually I wanted to be assured once more, I wanted to be certain, so I wanted re-validation from God, i.e. that he might speak to me the same way he did to them. I was hoping that should this happen, all my doubts as to my calling would vanished. The voice never came.
From the Small Cathechism:
but the Holy Ghost has called me by the Gospel, enlightened me with His gifts, sanctified and kept me in the true faith; even as He calls, gathers, enlightens, and sanctifies the whole Christian Church on earth, and keeps it with Jesus Christ in the one true faith.
I have this thesis, and let me run this by you. The same Gospel that calls me to faith in Christ is the same Gospel that calls people to minister on behalf Christ.
1 Cor 5:18 Now all things are of God, who has reconciled us to Himself through Jesus Christ, and has given us the ministry of reconciliation, 19 that is, that God was in Christ reconciling the world to Himself, not imputing their.
trespasses to them, and has committed to us the word of reconciliation
This is again not subjective but entirely objective, it is again extra nos. It is not dependent on a mystical experience. Since I have been reconciled to God by the message of the Gospel, I, by that same reconciliation have received something. I can then give that which I have received to others i.e. the Gospel so that others may be reconciled too. Therefore the minister is giving also what he has received, the reconciliation. Indeed, I am more convinced today that the minister is simply administering or dispensing that said gift.
It is one beggar telling another beggar where he found bread (didn't Luther say something like this?).