I've written before that you need a pastor. Now, being a pastor myself, I run the risk of being misunderstood. Allow me to be clear. You don't need me as your pastor. But, you do need a pastor.
Or to put it another way. The Church does not exist without the Pastoral Office.
We sort of know this to be true from experience. A pastor takes a call to another congregation and departs. This creates a vacancy. But what is vacant? Not the church. There are still plenty of people there. The Pastoral Office is vacant. No, not the pastor's office. But the divinely instituted office in which the pastor is placed by Christ himself, and from which the pastor serves "In the stead and by the command of Christ."
So, the church does not exist without the Pastoral Office. But why did Christ institute this office? Article V of the Augsburg Confession makes this crystal clear:
So that we may obtain this faith, the ministry of teaching the Gospel and administering the Sacraments was instituted. Through the Word and Sacraments, as through instruments, the Holy Spirit is given [John 20:22]. He works faith, when and where it pleases God [John 3:8], in those who hear the good news that God justifies those who believe that they are received into grace for Christ's sake. This happens not through our own merits, but for Christ's sake.
Our churches condemn the Anabaptists and others who think that through their own preparations and works the Holy Spirit comes to them without the external work.
Why did Christ institute the Pastoral Office? So that you may obtain this faith.
What faith? The faith confessed in Article IV: "People are freely justified for Christ's sake, through faith, when they believe that they are received into favor and that their sins are forgiven for Christ's sake. By His death, Christ made satisfaction for our sins."
So how is this faith obtained? "Through the Word and Sacraments, as through instruments, the Holy Spirit is given. He works faith."
All this is to say, The Pastoral Office is the guarantee that the means of Grace will be given, and the Holy Spirit will be active to create and sustain the faith that trusts in Christ alone.
Where the Pastor is preaching/teaching the Gospel, Baptizing and celebrating the Lord's Supper, there the Holy Spirit is living and active.