Russel Moore being spot-on here:
Over the past several years, we’ve had some evangelical leaders, and the politicians they support, ridicule the “weakness” implied in “Turn the other cheek.” If that were just the Bizarro world of cable television news, I would perhaps dismiss it. But several pastors have told me about how when they cited, parenthetically, “Turn the other cheek” or “Love your enemies,” they had someone ask afterward where they were getting their “liberal” ideas.
Another told me that after preaching on the Sermon on the Mount, a congregant told him, “We’ve tried the ‘Turn the other cheek’ stuff, it doesn’t work; it’s time now to fight.”
To be clear, the Sermon on the Mount doesn’t “work,” and it never has—if what we mean by “working” is seeing the world’s definition of success on the world’s timetable. Ending up crucified is no society’s definition of winning. That’s exactly the point Jesus was making. He turns all those definitions and expectations upside down.
Turning the other cheek is to "win" because it demonstrates obedience to and therefore love of God. Christianity is not a means to an end: it is the end in and of itself.
As a brief postscript, I can hear my "Piperian" brothers and sisters taking issue with "Christianity is the end." Isn't God the end? Yes. What I mean by Christianity is not the cultural expressions or our acts of religious devotion (at least not alone). It is the entirety of the system of belief which is based in God as the triune, self-revealed deity who made the world and all that is in it; who manifest in shadows in times before and ultimately in the person of Jesus, the Messiah; who continues to reveal himself to us in the Scriptures, in his Body, the Church (of whom he is the head) by the power of the Spirit who opens eyes and replaces hearts of stone with hearts of flesh that desire God above all else. Christians get God. We should wish to be Christian rather than any other societal, political, sexual, social, etc., etc., identity we could label ourselves with.
P.P.S: Also, for those of you who know I've been thinking a lot about pastors and preaching, Moore gives us this nugget a bit later on:
If every passage of Scripture—whether proverb or psalm or parable—must be turned into an epistle with a point by subpoint by sub-subpoint structure in order to be preached, then we are not actually teaching the Bible but something else: a systematic theology or an ethics manual. We are not saved by Christology; we are saved by Christ.