At the close of last year’s Christmas Eve service, I sat for a while in my empty church, reflecting on my 20-year ministry to a rather special congregation on the north side of Glasgow.

By 1am the watchnight worshippers had headed home or, perhaps, to the next Christmas Eve gig. Generous smiles and handshakes at the door suggested all had gone well. Hark the Herald Angels to start with O Come all ye Faithful to finish. And in between? A lights down period of quiet reflection; a time to hear again that familiar story; to put Mary and Joseph centre stage and ensure that enough emphasis was placed on Joseph’s ancestry, Mary’s virginity and the miraculous intervention of God.

With a flickering candle in one hand and a New Testament text in the other, I read again the evening’s sacred scripture: "The Holy Spirit will come on you, and God’s power will rest upon you. For this reason, the holy child will be called the Son of God.’

But for some other reason, I felt troubled and dispirited. On an evening when the words "joy" and "peace" had richly coated every note, syllable and handshake, curiously I felt bereft of both. At first, I could not work it out. As a typical Church of Scotland minister, I should have felt uplifted: a full church, a healthy collection for Christian Aid and, what’s more, lots of satisfied customers. Hymns we have always sung and stories we have always read. On this night one is expected to leave the choreography intact; it is not the night to rock the ecclesiastical boat. No probing questions or smart theological asides. Just tell it as it has always been told: orthodox, traditional, literal.

And therein lay the root of my predicament. It was the literal aspect that kept a man up too late on Christmas Eve.

No doubt good friends would have said: "Chill, Andrew." Others would have encouraged me to take heart from the fact that Christianity’s practical arm was once again served by monies raised that evening: cash that would help to keep alive the strong ethical imperative at the heart of the Jesus story. It was, therefore, plain daft to allow theology’s nuanced arguments to dull the sparkle of an otherwise festive evening.

And yet, the truth is, they had. By adding weight to the literalists’ case, I had let folk think, yet again, that the event of Bethlehem was merely historical. With it sounding more like an elaborate fairy tale, I had invited the congregation to suspend reason and believe six impossible things before breakfast.

Don’t get me wrong. The story shared by candlelight says something marvellously true about the Christ child. Nor do I doubt that the content of these narratives is built around memories of actual incidents. But other than the fact that a baby, called Jesus, was born in Bethlehem around the year 4BC, there is really not much more the historian can say on the matter. Yet, that was exactly what I had done: offered evidence as if from a policeman’s notebook, thereby perpetuating the lie that the Christian faith requires us to believe that if video cameras had been invented back then, I could now have shown recordings of shiny stars, angelic appearances and journeying kings.

During my moment of thoughtfulness I came to realise that life’s deepest and richest truths are often profoundly elusive.

"Like butterflies," said the late John Robinson, author of Honest to God, "If you try to pin them down you kill them."

That’s why the meaning of Bethlehem can only be truly expressed in the language of poetry and parable; or myth if you prefer. Christmas Eve is more in need of imagination than insight because its significance requires us to focus on what it means rather than on what actually happened.

So this Christmas my convictions are clear, albeit there will be the same familiar atmosphere within my much-loved parish church. The candles will be lit and the carol sheets will be at the ready but this year I’m promising myself to be more theologically honest. No more going home with fanciful, fairy tale assumptions destined to make Good News seem incredible.

Too much serious stuff is going on in the world for folk in my position to even risk the possibility of sounding remote, irrelevant or both. The late Bishop Robinson summed it up rather movingly in the late 1960s while addressing the vexed question of the virgin birth; he managed to convey my kind of Christmas Eve honesty.

He said: "The Virgin Birth? If it helps to see in Jesus God at work, well and good. But if it merely succeeds in convincing you that he was not 'one of us', then it’s much better that you shouldn’t believe it – for that was never its intention. I’d rather you suspended judgment than let it become a stumbling block. The main thing I am concerned with is that Christmas should be seen to be about the real world – the world of missiles and housing and unemployment in which we live. Jesus shows us that behind this world – incredible as it may seem – is a love which sets a value on persons that nothing can destroy."

It’s time this Christmas to disentangle the truth from the tinsel; time to tackle the stumbling blocks and present news on Christmas Eve that is both persuasive and compelling.

In the half century since Bishop Robinson wrote those words, other sciences have happily embraced society’s change of outlook and consciousness and made their search for truth less prescribed and much more open-ended.

Religion, however, has tended to move in the opposite direction. We may have outgrown the need to view God as "up there" or "out there" but, on the whole, we remain shackled to a confining orthodoxy that limits folk to a simple dogmatic choice: either take it or leave it. Therefore, if I’m asked whether I believe in the virgin birth and say "yes", then the questioner will probably assume that I accept it literally. However, if I say "no" then the consensus will be that I’m no longer a Christian; what a sad state of affairs.

For me, it’s time to travel beyond the literalists’ landscape; time to acknowledge that Luke and Matthew were not newspaper reporters. Although facts were for them significant, they were always secondary. As literate and imaginative thinkers, their passion was to highlight surplus meaning, metaphorical meaning, meaning more than literal and, by virtue of that, better able to pinpoint truth’s essence at the heart of the Bethlehem narrative.

No doubt some Christmas Eve worshippers will accuse me of undermining the Bible. Others (and by that I mean the growing number who are hanging on to the church by their fingertips) will hopefully see all of this as an attempt to enrich faith, a way of genuinely affirming the storytellers’ conviction that the God of life and love is eternally with us and for us, and not just on evenings reserved for candlelight and carol singing.

The Rev Andrew Frater is minister of Cairns Church, Milngavie.