In the recent issue of the European Journal of Theology, I discuss the role of Christians in democratic countries and argue that – under God's providence – the participation of Christians in society often leads to temporal blessings for those very societies. Western history provides many examples of this, the development of democracy being one of them.

Scripture also contains examples of this: Egypt was blessed politically through Joseph, and Babylon profited from Daniel. In the New Testament, God's blessing for the Church, with which it in turn should bless society, is at its core sharing Christ and his Spirit.

Christians testify of Christ and his kingdom in words and deeds. Christians love their neighbours with acts of service and sacrifice and let them taste Christ's love, hospitality, mercy, care and wisdom. They commit themselves to the relative good of their societies. Even if not fed by conversion and regeneration, such fruits are temporal blessings of God for the whole world.

Yet what should be the Christian response to today's post-Christian democracies? Contrary to secularised fellow-citizens, Christians are still connected to the historical feeding stream of democracy. Yet they have to rediscover that they are first and foremost members of the Church. If they do not let themselves constantly be formed there, their participation in the public life will easily secularise them.

In today's democracy they cannot but tolerate unchristian lifestyles and be ready for compromise on many points. Yet these compromises could weaken the convictions and lifestyles of Christians themselves. A renewed awareness of their position as resident aliens after decades of secular public dominance is indispensable to spreading God's blessing today. Without it there would soon be nothing left to spread.

This renewed awareness of their citizenship in 'the city of God' will liberate Christians from overly strong identifications with the present political realities. Their being 'Dutch' or 'British', their national or traditional or liberal values would then become too important. Christians today should not automatically identify with their liberal or their illiberal democracies, for any such identifications are secondary. Any secondary identifications should spring from conscious Christian neighbourly love and well-considered estimations about what will serve the temporary goods of this world.

A renewed focus on the coming Jerusalem will teach Christians that they share a much deeper bond with their brothers and sisters in other countries than with their compatriots. Realising this could perhaps give Christians a mediating role in present European affairs.

Christians could use their rootedness in the Church to contribute to the much needed renewal of democracy. Local churches or fragments of genuine communal life within churches could, in the wake of communal worship, loving each other and loving the neighbours, become breeding grounds for grassroots forms of commitment to the common good.

A local London parish, for example, managed to improve public policies on the housing of lower classes in its neighbourhood. An American local church convinced banks to loosen their grip on some fellow citizens in town during the credit crisis. In the Netherlands, Christians living in a multicultural apartment building with a degenerated, hostile and insecure atmosphere managed to forge new moments of communal interaction which brought peace to the building.

Perhaps in the future the Church will be more faithful to its scriptural calling by adopting such grassroots activities as the default mode of democratic participation, rather than the usual strategies which operate from the official democratic power centres.

Living in post-Christian democracies, and sometimes like Joseph or Daniel having to bear indirect responsibility for practices that contradict the aims of God's kingdom, demands frank and clear Christian prophecy. When witnessing to the lifestyle of the kingdom of Christ, Christians should freely refer to the biblical narrative and to God's truth. Our post-truth and post-democratic societies especially require that we speak truth to power, as Walter Brueggemann has defined Old Testament prophecy.

Dr Ad de Bruijne is professor of Ethics and Spirituality at the Reformed Theological University in Kampen, Netherlands. For the European Journal of Theology click here: http://www.paternosterperiodicals.co.uk/european-journal-of-theology