At a beautiful church service recently I encountered again a Gospel parable that left me, again, torn between sympathy and doubt. You will recognise Matthew 25: 35-40, for its phrasing has entered the idiom: ‘I was hungry and you gave me food … sick and you visited me … in prison and you came to me … a stranger and you took me in … naked and you clothed me … ’

The story is of a king praising his subjects for these kindnesses to him. This puzzles them: ‘When did we see you hungry, and feed you … a stranger and take you in…’ (etc)? The king replies: ‘Inasmuch as you did it to one of the least of these, my brethren, you did it to me.’ The moral Jesus is pointing to is double-headed: by serving your fellow men you serve God; furthermore God is watching you, so you had better behave to others as you would to Him.

That second thought, more admonitory, is unmistakable in Luke 12: 40-48 (‘Be ye therefore ready also: for the Son of man cometh at an hour when ye think not’). This time, Jesus’s parable is of a lord who, departing his household, leaves his steward in charge. Not expecting his master back soon, the steward starts abusing his privileges and neglecting the household. Foolish, because ‘the lord of that servant will come in a day when he looketh not for him, and at an hour when he is not aware, and will cut him in sunder’.

These are powerful parables whose message has easy purchase on the human imagination. In both, God is watching us: a kind of celestial CCTV. If we abuse any of our brothers and sisters, He will take it personally. If we are good to them, then a God who ‘seeth in secret, shall reward you openly’ (Matt 6:6).

I have a big difficulty with the central idea driving these stories. Recently reading Theo Hobson’s challenging book God Created Humanism has reminded me of it.

Mr Hobson’s argument is sometimes dense but its central thrust is nicely summarised in the book’s subtitle: ‘The Christian basis of secular values.’ Hobson thinks humanists and secularists should acknowledge that the fount of their moral sentiments is a religion which, though they may no longer adhere to it, still underpins their morality. Politicians and others loosely employ this argument when they talk (as is their wont) about ‘Judaeo-Christian values’. I cannot think why the ‘Judaeo’ has been tacked on here because Judaic values are significantly different from Christian ones and Christianity’s claims are more like Islam’s than Judaism’s, but nobody speaks of ‘Islamo-Christian values’, probably because we’ve recently stopped beheading people. I conclude that the anomalous insertion of ‘Judaeo’ is to avoid insulting Jewish opinion, which is likely to form a significant part of intelligent writers’ and politicians’ audiences in the West. But the anomaly is a useful pointer to the two objections that any argument that ‘our religion is part of us even if we don’t subscribe’ must encounter.

The first can be phrased by the rejoinder ‘Will any religion do, then?’; and the second by the rejoinder ‘Maybe religion does underpin “secular” morality, but that doesn’t make the religion true.’

Hobson does face up to the second rejoinder in his chapter ‘So what? How is Christianity credible?’ But the first is, I believe, fatal to his case. Once you have observed that every culture in human history has appeared to have its morality underpinned by its religion, yet that these religions appear to be founded on different Gods (or gods, or belief systems) which cannot all be true, a terrible likelihood occurs. What if the morality comes first, and the religion then absorbs it, and uses it?

Darwinism if not Darwin is all you need to explain the morality, and perhaps the religion too. Being social animals, humans need rules; and rules need authority. One basic rule must underlie all the subsidiary ones: that we must not behave in an antisocial manner; that we should help and support our fellow members of society and act, not for ourselves alone, but for family, friends and the whole community. Such a rule assists a society’s life chances.

Religion echoes, amplifies, elaborates, refines, tabulates and may even twist to its own advantage this fundamental social urge: but the urge pre-exists any particular religion. This is so obvious that the point is not worth labouring.

But if religion does not create secular moral sentiment, could it at least elevate it? And here I return to that lovely church service and those apparently moving words in Matthew’s Gospel. For I’m afraid that, on consideration, these parables degrade rather than elevate. They debase our inborn Darwinian concern for fellow humans. Read the New Testament, and ask yourself what happened to virtue being its own reward.

Our inbuilt ‘secular’ morality whispers that kindness to others is good. Good in itself. Good because that’s what ‘good’ means. Not good because (who knows?) God may be doing a bit of plainclothes detective work among us, and dressing up as a beggar, prisoner or invalid. The master’s steward ought to look after members of his master’s household not because the master may arrive secretly in the night, but because those people matter, and are human beings just like him. Inserting God as a spy cheapens what should be the moral basis of our civility.

I cannot forget the vicar who wrote to me after I had criticised the notion of heavenly reward for good works, to ask how he could be expected to tell his congregation not to shoplift if he were no longer able to tell them that stealing was no way into Paradise. Perhaps one should thank him for not dressing up the crude basis of Immortalism as anything other than the concealed truncheon it really is. And tell him, too, that Theo Hobson’s book should be rewritten under the title: Humanism Created God: the secular basis of Christian values. We humanists can do better than Matthew’s gospel. Virtue is its own reward.