Absolutely! Because the folks that we send to do the work of evangelism come from our home churches. This point has been driven home to me in a fresh way the last two weeks as my family has hosted missionaries our church sent out to an unreached people group 5 years ago. By the grace of God, they were able to see several people converted and plant a church among these people who formerly had no church. Their time on the field has been hard. And they have been refined by the Lord--at some points in very severe ways. Listening to their stories of the obstacles that stand in the way of evangelizing on the last frontier reminds of the need to remain faithful in working for biblical reformation here at home. The vision of American Christianity that much of the Muslim world has is quite different from the press reports we write and read about ourselves. Too often, the faith that we export via our missionaries is anemic, severely deficient of doctrinal strength. If the sending churches have an undetected (or at least untreated) virus, there is great probability that the receiving people groups will be infected as the gospel takes root among them.
In the last century Austin Phelps of Andover Seminary undertood this when he said, "If I were a missionary in Canton, China, my first prayer every morning would be for the success of American Home Missions, for the sake of Canton, China" (Call of the South, published by the Publicity Department of the Home Mission Board of the SBC, Atlanta, 1920, p 217).
Reformation and missions go hand-in-hand. If we do not strengthen our churches at home, we will ultimately undermine the effects of the gospel abroad. Do not shrink back from the hard work of reformation. Do not let others around you ignore its importance. Don't let anyone intimidate you into thinking that if you are concerned to order your life and see churches ordered by the word of God that somehow that undermines the evangelistic missionary impulse that the gospel is to have in the world.
And if you are a pastor, don't be so selfish with your time! There are other pastors who need to think about the things you're thinking about. If you simply order your own life and your own church and you're not winsomely trying to come along your brother pastors to challenge them and encourage them to start thinking about important things like church life and health, then you are not engaged enough in the work of reformation.
We need to continue to send missionaries--may God raise up even more! But we must never, ever cease the work of reformation.
I have written more extensively on this subject in a chapter entitled, "Reformation and Missions," in the book, Reclaiming the Gospel and Reforming Churches (Founders Press, Cape Coral, FL, 2002).