“The idea of church as contrast-society does not mean contradiction to the rest of society for the sake of contradiction. Still less does the church as contrast-society mean despising the rest of society due to elitist thought. The only thing meant is contrast on behalf of others and for the sake of others, the contrast function that is unsurpassably expressed in the images of ‘salt of the earth,’ ‘light of the world,’ and ‘city on a hill’ (Mt 5:13-14).
Precisely because the church does not exist for itself but completely and exclusively for the world, it is necessary that the church not become the world, that it retain its own countenance. If the church loses its own contours, if it lets its light be extinguished and its salt become tasteless, then it can no longer transform the rest of society. Neither missionary activity nor social engagement, no matter how strenuous, helps anymore. …
What makes the church the divine contrast-society is not self-acquired holiness, not cramped efforts and moral achievements, but the saving deed of God, who justifies the godless, accepts failures and reconciles himself with the guilty. Only in this gift of reconciliation, in the miracle of life newly won against all expectation, does what is here termed contrast-society flourish.”
—Gerhard Lohfink, Jesus and Community: The Social Dimension of Christian Faith (SPCK, 1985) as quoted in Eckhard J. Schnabel, Early Christian Mission: Paul and the Early Church (IVP, 2004), 1577-1578.