It is likely important to keep in mind that the above should not be understood as the erasure of distinctions. For example, think of the early church permitting seekers, hearers, and kneelers to join them for the first part of a worship service (Service of the Word), but then sending them out with their catechetical instructors during the Service of the Table (this is helpfully illustrated from Apostolic Tradition by Hippolytus in at least 3 books by Robert Webber: Liturgical Evangelism, Journey to Jesus, and Ancient-Future Evangelism).
Keep in mind, as an example of this approach, the revival in Israel under Ezra/Nehemiah. The revival did not occur until the walls had been restored. This distinction enabled a sense of identity to be realized. Secondly, they then flung open the gates for 6 out of every 7 days and practiced hospitality. On the Sabbath, they closed the gates, a visitor or sojourner was welcome to stay but not to do business. Being in the city, however, did not mean they could move out of Solomon’s Colonnade or the Court of the Gentiles, and past the balustrade (or Soreg), which functioned in a manner equivalent to being barred from the Service of the Word in the practice of the 2nd & 3rd century Church (as referenced briefly above).
In order to think about this accurately and fairly, I would basically forget about contemporary church practice, as it is too far removed from anything biblical to serve as a useful bridge to comprehension of this conversation. The Bible cannot imagine an assembly of believers that doesn’t have a corresponding and inextricable social/civil culture, for example.
In our milieu we invite a seeker into what we tend to view as equivalent to the Holy Place because there is no other functioning representation of our belief. The biblical model could distinguish between the nochri, the ger, the ger toshav, and the ger tzedek, for example, any of whom might live in the village, but who were treated differently depending on their status. (to some degree I am collapsing development over time into a single concept here, but the point remains)
From Belong, Believe, Behave, we tend to over-emphasize Believe, under or over emphasize Behave, and practically forget about Belong because we ourselves experience very little sense of belonging. If we don’t like the congregation, we simply move to another of the 75 options in our town, unable to imagine what it means to be part of the village congregation. True belief and true behavior springs from knowing we belong, however, and this is a massive part of what is malfunctioning in our environment. (I have also just massively underserved the dynamic interplay of the three concepts, but I can’t write a book here.)
The view described above as “Roman” defies the reality of how human nature functions and asks for a declaration of belief as a credential of immediate and total inclusion. There is nothing corresponding in Scripture. I know immediately how any person of baptistic background will respond, but this fails to understand that biblical baptism is a single act among many in a lengthy—not just process—lifestyle of growing immersion into the entire culture of belonging, believing, and behaving.