Evangelical fundamentalists are my people. Some of them wish they could disown me, and some days I wish they could too, but our relationship is a fact of history–which is to say that it is God’s Providence. It is among these people that God has called me to serve, and to serve not just as a sheep, but also as a shepherd. Jesus is the Chief Shepherd, of course. All the sheep are really His, and all His people are His sheep. But some of us are also shepherds, under His direction. The Church being what it presently is, there are a lot of different sub-flocks, divided both by geography (which is fine) and by doctrine/history (which is not). There are Anglican shepherds, Methodist shepherds, Baptist shepherds, Eastern shepherds, and so on. I am an evangelical shepherd.
I have friends in other traditions who urge me to convert to their tradition. They argue that in my tradition, the sheep are sick. In their traditions, they say, there is medicine for this sickness. (Of course their traditions have their own weaknesses, but let’s leave that aside for now.) Granting the correctness of the diagnosis–and at some points it is correct–how could I leave for that reason?
What kind of a shepherd leaves a flock because it is sick? A good shepherd heals the sick, and is willing to accept medicine from whoever has it to give.
“You have no right to this medicine,” says the stingy traditionalist, “unless you come serve in our corner of Christ’s great flock. This medicine belongs only to us.” But no. What do they have, that they did not receive as a gift? And if they received it as a gift, why do they boast as though they did not? If the medicine heals, then it comes from Christ the Great Physician, and if it comes from Christ, it is for all His sheep: “Freely you have received; freely give.”
Full Contact Christianity 
Short comment: Amen, Tim.
Long comment: I found your post this week particularly thought provoking. I think that sometimes people (sheep and shepherds alike) feel safer in their own sphere, with their own set of labels of ‘them’ and ‘us’. I can understand how that comes about, but it saddens me to see that fear – we are, of course, repeatedly warned to be discerning of false teaching, but I don’t know of anywhere in Scripture that says we are to refuse to even listen to an idea that doesn’t come from our particular brand of ‘true shepherd’. Surely the first and foremost consideration is to listen to every idea, but test it against Scripture? That is what the Bereans were commended for, was it not? How often do we miss out on a gem of priceless worth by being too scared of ‘false doctrine’ to even listen, or worse, too arrogantly sure that we, and only we, have the ‘right doctrine.’ Having been guilty of this in the past, and liberated from it, I *try* now to not even ‘categorise’ anyone – I find asking them what they believe on various issues as they come up in discussion is far less likely to result in wrong assumptions. And I pray that the Lord keep my heart open to new ideas, even (especially?) those that make me squirm!
And of course, Tim, your comment on sick sheep: I have never refused to treat a sick animal – and have been cut to the core when prevented from giving treatment by the owner – how much more should that be true for the two legged kind of sick sheep!