Why does the church exist? Is it to clothe the naked, feed the sick, liberate the oppressed? Is it wrong for churches to do this? Not at all; in fact, it is quite good and necessary to our Christian witness. But they’re not the main thing.
As Martyn Lloyd-Jones argues in Preaching and Preachers, those things are good, but they are symptoms of a greater problem. A sin problem. The problem of being separated from God. And so, it falls upon the church to bring people into a right relationship with God. He explains:
It has come into the Church and it is influencing the thinking of many in the Church—this notion that the business of the Church is to make people happy, or to integrate their lives, or to relieve their circumstances and improve their conditions. My whole case it that to do that is just to palliate the symptoms, to give temporary ease, and that it does not get beyond that.
I am not saying that it is a bad thing to palliate symptoms; it is not, and it is obviously right and good to do so. But I am constrained to say this, that though to palliate symptoms, or to relieve them, is not bad in and of itself, it can be bad, it can have a bad influence, and a bad effect, from the standpoint of the biblical understanding of man and his needs. It can become harmful in this way, that by palliating the symptoms you can conceal the real disease. . . .
The business of the Church, and the business of preaching—and she alone can do this—is to isolate the radical problems and to deal with them in a radical manner. This is specialist work, it is the peculiar task of the Church. The church is not one of a number of agencies, she is not in competition with the cults, she is not in competition with other religions, she is not in competition with the psychologists or any other agency, political or social or whatever it may chance to be.
The church is a special and a specialist institution and this is a work that she alone can perform. (30-32, formatting mine)