Q9: Indeed. Frank, do you personally see any use for the teaching of the marks of the true church?
A9: I think it's somewhat amusing that in a debate about separation — that is, the demand that an individual must cut himself off from anyone with sufficient theological flaws -- Daniel is making much of ecclesiastical uses of doctrine. He can't really decide what he's demanding or when the demand became evident in the practice of the church, so he treads back to one set of doctrines which, he hopes, look enough like his demand to make some case for cutting off pastors with a lifetime of valuable and faithful ministry because of their associations with questionable characters.
That said, here are three uses of the 3 marks:
1. Didactic: that is, to systematize the teaching of Scripture for the sake of teaching the faithful about the purpose of the church. It creates catechories [sic] for what Scripture teaches in a more-organic way.
2. Ecclesiological: that is, it defines what a church is and therefore what it is not. It sets the boundaries for mission and practice.
3. Missiological: that is, it creates priorities for the practical work of the church. Items not inside the three marks are secondary at best and therefore are not priorities for those who are seeking to do what the church ought to do.
Thanks for asking.