Diognetus’ diagnosis...

He was just there to buy his dinner.

In a Constantinople fish shop in 1436, a young theology student notices and rescues some papers set aside for wrapping fish. It’s a hitherto unknown and anonymous letter which we now know as “The Letter to Diognetus”.

Written in the second century, the letter describes the Christian way of life. In one section the author notes that while Christians are no different from others in terms of country, language, or clothing they are able to display “their wonderful and confessedly striking message of life”. A little later he continues: “They marry, as do all [others]; they beget children; but they do not destroy their offspring. They have a common table, but not a common bed.”

You may not have heard of this letter, but you will have heard of a phrase in the letter which we mistakenly think is from the Bible: Christians are “in the world but not of the world” (a great trick-question for your next church quiz!).

We trot this phrase out, but unpacking it is far from simple. What does it mean to be in “the world of the UK” but not of “the world of the UK” in 2025? A world that seems crazier than ever. A world where life and relationships are often fear-filled, where we don’t know who we are, where we are afraid to love and be loved. A world that still is living off the borrowed capital of a Christian heritage, but where we are marginalised and often vilified. What does “in the world, but not of the world” mean for our churches and the culture of our communities?

Three temptations to avoid

It’s tempting for us to just look in. This is our baptised “flight” response. We retreat, huddle together for warmth and comfort and pray for Jesus to come back soon.

It’s tempting for us to just lash out. This is our baptised “fight” response. We get red-faced, and our going on the offensive quickly turns into being offensive.

It’s tempting for us to just look like. Not only is it awkward and embarrassing being counter-cultural, it’s tiring. And we’re so tired. Can’t we just take the path of least resistance? Can’t we just keep our heads down and go with the flow?

Of course in reality we exhibit all of these postures, which are distorted and yet do point to God’s truths. We are a royal priesthood and holy nation, a distinct and separate community in which God’s people are formed into the image of Christ. As God’s people we should have zeal for God’s glory, knowing that we must speak out against sin and injustice wherever it is found. Finally, even while being counter-cultural, as Christians we should recognise a “fellow-feeling”. Christians are not a different species. We are still humans living and working together with other humans who do not know Christ, swimming in similar cultural waters.

Looking up and looking out

But is there a better posture, a more Biblical posture? The gospel calls us to another way. A way that looks up and looks out into a world that is crying out for hope. A way that engages with the world around us by understanding its foundations, speaking boldly into its culture, and displaying the gospel. A way that is able to address both people’s felt needs and their fundamental need of Christ. A way that understands as complementary our calling to have dominion – to fill and subdue the earth – and our calling to make disciples of all nations.

We hope this column will show how we can cultivate such a posture, challenging our culture’s stories, offering constructive alternatives under Christ’s Lordship, demonstrating without fear our wonderful and confessedly striking message of life.

See response from en readers to this article here: In it - or not in it?