“One of the slogans on the posters and banners in front of St Paul’s Cathedral has been ‘What would Jesus do?’ This started life in the US some years ago, with people wearing wristbands with WWJD on them. It’s one of those things that looks wonderfully obvious, a quick way to the right answer.

Well, an archbishop is hardly going to suggest that it isn’t a good question to ask! All the same – the idea that it somehow provides a nice short cut to the truth needs a bit of challenging.

For a start, Christians don’t believe that Jesus is there just to give us a good example in every possible human situation. The Jesus we meet in the Bible is somebody who constantly asks awkward questions (especially questions addressed to religious people, moral people and rich people – all the sorts of people involved at St Paul’s…) rather than just giving us a model of perfect behaviour. Faced with what looks like a simple challenge about whether you pay taxes to the Roman Emperor or not, he famously shrugs it off, saying, ‘Give Caesar what belongs to Caesar and give God what belongs to God.’

In other words: don’t just imitate me: think. What’s the exact point at which paying taxes to the Empire gets in the way of serving God? What’s the exact point at which involvement in the ‘empire’ of capitalist economy compromises you fatally?

It may not be easy to answer this straight away, so don’t expect to become a hero of conscience overnight. And, just to rub it in, there are other places in the Bible where Jesus prods us to ask ourselves about our motives before we embark on grand gestures. Are we doing this for the sake of the real issue – or for an audience?

What matters about Jesus isn’t that he always tells us simply what to do. What matters is that he is there – claiming the right to probe our motives and stretch our minds. Faith isn’t about just his teaching or his good example but his whole life, his whole being. That whole life expresses a committed love that won’t go away whatever we do, and so has the right to ask the awkward questions: the questions posed to us by his birth in poverty and his childhood as a refugee – and the still bigger challenge of his apparent failure and his death.

And that challenge is: what if all your standards of success and failure are upside down? Christmas doesn’t commemorate the birth of a super-good person who shows us how to get it right every time, but the arrival in the world of someone who tells us that everything could be different.

WWJD? He’d first of all be there: sharing the risks, not just taking sides but steadily changing the entire atmosphere by the questions he asks of everybody involved, rich and poor, capitalist and protester and cleric.

Christmas tells us two big things. First, what changes things isn’t a formula for getting the right answer but a willingness to stop and let yourself be challenged right to the roots of your being. And second, we can find the courage to let this happen because we are let into the secret that we are in the hands of love, committed, unshakeable love.

I hope that something of that great secret will find its way into your celebrations this year. Happy Christmas!”