One of the questions that mission theology and missionaries have asked more than any other question is one which you may think is daft, what is mission? Andrew Kirk even wrote a book with that title. Surely as a missionary, a missionary trainer and a missional theologian, that's a question I should have been able to answer years ago; but it keeps on coming up.
This is, perhaps a question that Evangelicals have come to later than their ecumenical or Roman Catholic brothers and sisters. We were concerned not to lose sight of the gospel, which I would suggest the ecumenical movement did in the 1960s to 1980s. The gospel transforms individual lives in the form of a conversion, a metanoia, a change of mind. The idea that the gospel transforms society, apart from sounding dangerously close to Communism, lost the individual aspect of transformation. So there we stayed for years.
The recapture of an eschatological approach to mission by Evangelical Theologians like George Eldon Ladd and C. Rene Padilla have revived the idea of Inaugurated Eschatology. The life, death, resurrection and ascension of Jesus Christ inaugurated the kingdom of God and in his second coming he will fulfill it. In the mean time the Church, with the living presence of God in the Holy Spirit, lives out the values of the kingdom of God now.
Now those "values of the kingdom of God" were demonstrated primarily in every aspect of the birth, life and teaching of Jesus as well as the manner of His death and resurrection. Clearly the rest of the New Testament also bear witness to this as well as the Hebrew Bible.
So the answer to the question I posed in the title is, both. Individual conversion is important as well as societal transformation. The call to repentance and faith (discipleship), the planting of living communities of faith (Churches), the care of the poor, the confrontation with the powers of evil (human and demonic) and the care of creation are all parts of the values of this kingdom inaugurated by Jesus, announced, lived out and worked towards by the Church and to be fulfilled in Jesus' second coming.