Jesus and the apostles were not just focusing on how to include as many as possible in the church through evangelism, but also on how to exclude unbelievers, heretics and sinners who refuse to repent. If we want healthy churches today, we have to start talking about who we should exclude from our midst.
When lots of disciples left Jesus because they couldn’t understand his teaching on eating flesh and drinking blood, He let them go and checked if the apostles would want to go as well (Jn 6:67). He later taught them that sinners should be excluded from the church if they refuse to repent and ask for forgiveness, they should then be viewed as pagans (Mt 18:15-17).
Paul speaks about this extensively in 1 Cor 5, where he commands the Corinthians to exclude a brother who had sex with his stepmother. He points out that this doesn’t mean that Christians should not have any contact with sinners, the problem is when they call themselves Christians but still refuse to repent from their sin:
I wrote to you in my letter not to associate with sexually immoral people— not at all meaning the people of this world who are immoral, or the greedy and swindlers, or idolaters. In that case you would have to leave this world. But now I am writing to you that you must not associate with anyone who claims to be a brother or sister but is sexually immoral or greedy, an idolater or slanderer, a drunkard or swindler. Do not even eat with such people.
What business is it of mine to judge those outside the church? Are you not to judge those inside? God will judge those outside. “Expel the wicked person from among you.” (1 Cor 5:9-13)
Early Anabaptism that emphasized free will and freedom of religion wasn’t just keen on baptizing believers, but also excluding unbelievers. The practice of the ban was as central to early Anabaptists as baptism or nonviolence.
Now, there are definitely cases of this being misused, when believers refuse to greet or get to know unbelievers. Unbelievers should be very welcome to join church meetings and we should evangelize relationally. But we should not call non-Christians Christians. That’s what this is all about.
The consequences of ignoring this are devastating. Here in Sweden, 85 % of the Lutheran Church’s members don’t believe in Jesus. Hence, its bishops have started to claim that all religions lead to God and that Jesus isn’t necessary for salvation. In other words, they cease to be Christian as well. And one is free to not be a Christian, but then one should not claim to be a bishop.
Charismactivism 
I have to agree with pretty much all that was said. Jesus was not about maximum membership at any cost. Tell them the Gospel…if they don’t accept it, shake the dust off your sandals and leave. Unfortunately, too many churches are desperate for members and will do desperate things to get those members, including watering down the Gospel and all the traditions that made church……church.
I’m not sure I get the connection between excluding the unrepentant and the shift in the Lutheran churches, maybe because I don’t know any of the back story there. Is the implication that failing to exclude inclusivists has led to whole churches becoming inclusivist? Did the non-inclusivists just leave or have they changed their theology?
I’m only modestly familiar with the ban and it is one one of the mennonite distinctive that I’m not really on board with yet.
One might trace this trendency back to the forced conversion of everyone within the boundaries of the Roman Empire to become christian, to be baptized without repentance or commitment to Christ. Church discipline became confessional absolution, or merely sacramental absolution through priestly blindness, and of no practical or spiritual significance.
Micael, I wonder how you would view gay Christians who are ‘active’. I am gay but celibate as that is what I believe the Lord calls me to be, but if a gay Christian walked into your church and made it known he was in a relationship, would you still welcome him/her to your church?