(Tim) Under "What is Gospel-centered ministry, really...," there's been a lengthy series of exchanges in the comments concerning whether it's proper to preach evangelistic sermons to established churches. This is an exceedingly important discussion and I want to encourage readers to go down and read those comments in their proper context. But knowing some won't go there, here is my most recent response which can, to some degree, stand on its own. Whatever else you don't read, make sure not to pass over the critically important quote from Luther here recorded.
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Augustine said, "Many sheep without, many wolves within." From the
founding of the Church, this has been the universal experience of
pastors as we care for our flocks. Yes, the Epistles demonstrate a
presumption that letters to believers are letters to believers. It's
hard to imagine how they could have been written otherwise. "To those
purporting to belong to Christ who are a part of that organization
purporting to be a true church in Galatia?" It doesn't work.
But do the Gospels, Acts, and the Epistles provide evidence that our
Lord and His Apostles called the faith of those marked by the signs of
the Covenant into question? The answer to that question is an emphatic,
"Yes!" How long shall my list be? Think of those Christ contradicts,
telling them their father is not God, but the Devil (John 8:38
& ff.). And if we want to let ourselves off the hook by dismissing
Christ as our paradigm for pastoral care today under the rubric of His
omniscience, let's move to the Apostolic warning given to Simon Magus in
Acts 8. Or on to the many exhortations to baptized believers recorded
in the Epistles carefully calculated to warn against and expose
presumption--including the Letters to the Seven Churches (eg. Revelation
3:1-6).
So yes, we are to preach to our people normally addressing them as
true believers. But we also must test ourselves to see if we are in the
faith and call our flock to follow us in this discipline...