How Does a Gathering of People Obtain Church Authority?

Churches have authority.  This is seen through the whole New Testament, but for the sake of this post, I'm assuming that point.  How do the churches get that authority?  This is a theme brushed over in the latest series, yet unfinished, reviewing Kevin Bauder's chapter on Landmarkism (pts. 1, 2, 3, 4, 5, 6).

Yesterday I got a mass email from 9 Marks, Mark Dever's organization, which purports to specialize in ecclesiology.  I clicked on the link, and surfed to the latest journal, which explored various facets of church authority, and one of the articles, that caught my attention, by the Editorial Director of 9Marks, Jonathan Leeman, was entitled, "The Nature of Church Authority."  After his introduction, the following was Leeman's first section:

In fact, I don’t think the idea of church authority needs to mystify or scare us. It’s really quite simple. To strip off all the layers and whittle it down to its barest minimum, church authority is nothing more or less than two or three people agreeing about the gospel. 

Again I say to you, if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. For where two or three are gathered in my name, there am I among them. (Matt. 18:19–20) 

Suppose you and dozen other people are living on a desert island. You find a Bible, read it, and become convinced of the truths of Christianity. You repent and believe. You’re now a Christian, or at least you say you are. You share the gospel with two others. They, too, repent and believe. The three of you can now gather in Jesus’ name, because it’s no longer just you saying you’re a Christian; they’re saying it, too. 

The authority of your church of three consists entirely in your agreement with one another about Jesus and about each other.

I had never heard what he wrote in my entire life.  Had I missed something?  Is the above actually taught in Matthew 18, because it had never occurred to me.  Is that what people have really believed about church authority, that it is found in the agreement of two or three people?

As you continue in Leeman's article, if I am reading him correctly, he expands upon the above by saying that when two are three in gathered in Jesus' name, they have church authority.  He then defines "in Jesus' name" as, one, "agreement with one another about the good news of Jesus," and, two, "an agreement that the other two persons possess genuine faith in the good news about Jesus." I really don't get Leeman's point, if he's not saying that two or three people can be a church if each one of the two or three agree that the other one or two are saved people.  He says that a church can go public if it has two or three like this in one place who will agree.  Matthew 18 is for him the proof text for that.

Again, I have never heard that teaching from Matthew 18 in my entire life.  If I am representing him properly, then it is at least an attempt at a biblical basis for churches starting without the authority of another church.  In this case, he doesn't even mention baptism.  It can be a church without baptism at all.

I have understood the section in Matthew 18 to be an already existent church with authority.  Two or three witnesses agreeing is enough for a church to loose in church discipline.  The Old Testament standard for establishing the truth of something or the guilt of someone is two or three witnesses. A person's word is established by two or three witnesses.  When a church functions, it has the authority of Jesus Christ there.  Heaven is in operation on earth.

Matthew 18 is not providing a definition of a church, but it is helpful.  It's obviously a usage of the word "church" by Jesus in the gospels.  It is dealing with people in a single location.  It isn't universal.  A church does have authority, because it can add or subtract members.  The Lord teaches this.  He approves.

Matthew 18 is not speaking of the formation of a church by two or three without church authority.  It is not a passage teaching this.  Teachers like Leeman should not rely upon Matthew 18 as a passage to teach on the origination of a church.  It is teaching on church discipline for an already established, authoritative church.  A church has authority to discipline.  It must be a church.  To be a church, it must have that authority by means of another church.

Leeman compares these two or three agreeing to start the church to the start of any organization by a few people agreeing to start.  These two or three, he says, are ready to baptize too, if they agree that a new person should be baptized.  This idea is not in Matthew 18.  People don't suddenly have authority as a church because there are two or three of them, who agree that each other is saved.

I'm not going to go to all the passages that teach it, but authority passes from Jesus to a church to another church.  A church sends out evangelists.  They have the authority from that church to baptize.  That assembly becomes a church because a church says it is a church.

Furthermore, someone doesn't come into a church without the church.  Someone doesn't get dismissed from a church without the church.  A church doesn't start without the church.  The authority comes through church to church to church.  That is the pattern of the New Testament.

Leeman really does get it backwards.  Authority doesn't proceed from people agreeing.  Authority proceeds from a church, which proceeds from Jesus, the Head of the church. The two or three don't remove someone from a church.  The church removes someone.  Those three get authority from a church.  They don't become a church because they agree they are one.