Some of the saying of Jesus in Luke chapter 8 are surprisingly dark, when we try to read them with fresh eyes. For instance, he says: 'No one lights a lamp and hides it in a jar or under a bed. Instead, he puts it on a stand, so everyone can see the light.'
We might hear that with echoes of songs about candles shining in small corners, and think about how important it is to witness to our faith. But he goes on, 'There is nothing hidden that won't be disclosed, and nothing concealed that won't be made known' (16-17).
So it's more like a warning, or a threat, than it is a word of encouragement. Jesus himself is the light, the light of the world; he lights up all the dark corners, the secret things that we'd prefer to keep hidden.
Nowadays, that rings more true than ever it did. I'm late to this, but I've become engrossed in the HBO series The Wire. Running from 2002-2008, it's gripping stuff – but what's extraordinary, watching it for the first time just a few years later, is how primitive the technology looks. In the first series someone even has to explain what texting is.
Now, thanks to Facebook (founded 2004), Reddit (2005), Twitter (2006) and Instagram (2010), our whole lives are online. Employers trawl social media to find out about job applicants. Posts on Facebook can get people fired – or hired. That light-hearted tweet can be a life-changing disaster, as Justine Sacco discovered when she joked about not getting Aids before setting off for South Africa.
And it's not just over-sharing that gets people in trouble – things they would really, really rather no one knew at all are fair game for hackers and whistle-blowers. The so-called Paradise Papers have exposed the lengths to which the rich and famous go to pay as little tax as possible. Before that it was the Panama Papers; and before that, the revelation of how Britain's MPs milked a dysfunctional expenses system caused reputational damage to Parliament from which it has yet to recover.
At the same time the internet's opened up a world of temptation that can be completely private. There's an epidemic of online pornography. We can live second lives through our computers and no-one in the real world needs to know.
So Jesus's words are troubling, in at least two ways. One is that we're challenged to live with personal integrity, so that when the light shines and reveals everything in our lives, there's nothing that we don't want to be seen.
The other is that we're challenged to develope an honesty with other people, about our faults and failures. We don't have to be indiscriminately open – that doesn't help anyone – but relationships of trust are the best way of keeping the dark at bay.
Christians of all people should be those with nothing to hide. Our hallmark should be transparent goodness. That we often fall so far short of this is a mark of our human fallenness and fear; we're imperfect disciples. But we are disciples neverthless, and as Jesus says: 'I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life' (John 8:12).