I recommend you read this article entitled, “Mission: A Problem of Definition” by Keith Ferdinando from Themelios issue 33-1 (html | pdf). He takes four major ideas of what the church’s mission may be and shows which one he thinks is right. He considers the mission dei, the cultural mandate, social action, and making disciples of all nations. Here are some of quotes I found key for where I was at when I read it some months back:
Social change occurs through those who have been transformed by the gospel – through transformed communities of God’s people who become salt and light in their societies. It is fruit rather than substance of mission. Communication of the gospel in its richness is the most significant “social action” that missionaries can undertake (58, emphasis mine).
Certainly the extent of Christian engagement with the world is not limited to disciple-making but includes involvement in every area of life – all for the glory of God. The problem, however, is that if the making of disciples is subsumed under a category of mission which is much broader and far more inclusive, its absolute importance risks being compromised. Stott makes something of an allusion to this concern: “The main fear of my critics seems to be that missionaries will be sidetracked.” However, the issue is rather that churches in general would lose sight of the primary importance of making disciples and see such activity as simply one of many things that they are called to do… There is a danger of marginalisation of disciple-making if its distinct and unique nature is not specifically recognised and singled out as the great work of the people of God – the work that they alone can do (58-59, italics mine except for the underlined one).
The appropriate response may be loudly to reaffirm a disciple-making definition of mission; perhaps more realistically it may be to accept the irreversibility of “lexical entropy” and to develop new expressions – apostolic mission perhaps – to assert the church’s primordial and unconditional responsibility to make disciples. The importance can scarcely be overstated. The great theme of Scripture is God’s redemptive mission to call a people for his own glory among whom he will dwell; and those he calls are in their turn to engage in mission as his co-workers by making disciples of Jesus Christ. Definitional ambiguities must not be allowed to obscure the absolute centrality of that vital task (59, italics his).
I love Ferdinando’s clarity to what he thinks the mission is. And, on the whole, I agree with him. Read the whole thing.