Don't feel embarrassed if you've never heard of William Lane Craig. He parades himself as a philosopher, but none of the professors of philosophy whom I consulted had heard his name either. Perhaps he is a "theologian". For some years now, Craig has been increasingly importunate in his efforts to cajole, harass or defame me into a debate with him. I have consistently refused, in the spirit, if not the letter, of a famous retort by the then president of the Royal Society: "That would look great on your CV, not so good on mine".

Craig's latest stalking foray has taken the form of a string of increasingly hectoring challenges to confront him in Oxford this October. I took pleasure in refusing again, which threw him and his followers into a frenzy of blogging, tweeting and YouTubed accusations of cowardice. To this I would only say I that I turn down hundreds of more worthy invitations every year, I have publicly engaged an archbishop of York, two archbishops of Canterbury, many bishops and the chief rabbi, and I'm looking forward to my imminent, doubtless civilised encounter with the present archbishop of Canterbury.

In an epitome of bullying presumption, Craig now proposes to place an empty chair on a stage in Oxford next week to symbolise my absence. The idea of cashing in on another's name by conniving to share a stage with him is hardly new. But what are we to make of this attempt to turn my non-appearance into a self-promotion stunt? In the interests of transparency, I should point out that it isn't only Oxford that won't see me on the night Craig proposes to debate me in absentia: you can also see me not appear in Cambridge, Liverpool, Birmingham, Manchester, Edinburgh, Glasgow and, if time allows, Bristol.

But Craig is not just a figure of fun. He has a dark side, and that is putting it kindly. Most churchmen these days wisely disown the horrific genocides ordered by the God of the Old Testament. Anyone who criticises the divine bloodlust is loudly accused of unfairly ignoring the historical context, and of naive literalism towards what was never more than metaphor or myth. You would search far to find a modern preacher willing to defend God's commandment, in Deuteronomy 20: 13-15, to kill all the men in a conquered city and to seize the women, children and livestock as plunder. And verses 16 and 17 are even worse:

"But of the cities of these people, which the LORD thy God doth give thee for an inheritance, thou shalt save alive nothing that breatheth: But thou shalt utterly destroy them"

You might say that such a call to genocide could never have come from a good and loving God. Any decent bishop, priest, vicar or rabbi would agree. But listen to Craig. He begins by arguing that the Canaanites were debauched and sinful and therefore deserved to be slaughtered. He then notices the plight of the Canaanite children.

"But why take the lives of innocent children? The terrible totality of the destruction was undoubtedly related to the prohibition of assimilation to pagan nations on Israel's part. In commanding complete destruction of the Canaanites, the Lord says, 'You shall not intermarry with them, giving your daughters to their sons, or taking their daughters for your sons, for they would turn away your sons from following me, to serve other gods' (Deut 7.3-4). […] God knew that if these Canaanite children were allowed to live, they would spell the undoing of Israel. […] Moreover, if we believe, as I do, that God's grace is extended to those who die in infancy or as small children, the death of these children was actually their salvation. We are so wedded to an earthly, naturalistic perspective that we forget that those who die are happy to quit this earth for heaven's incomparable joy. Therefore, God does these children no wrong in taking their lives."

Do not plead that I have taken these revolting words out of context. What context could possibly justify them?

"So whom does God wrong in commanding the destruction of the Canaanites? Not the Canaanite adults, for they were corrupt and deserving of judgment. Not the children, for they inherit eternal life. So who is wronged? Ironically, I think the most difficult part of this whole debate is the apparent wrong done to the Israeli [sic] soldiers themselves. Can you imagine what it would be like to have to break into some house and kill a terrified woman and her children? The brutalising effect on these Israeli [sic] soldiers is disturbing."

Oh, the poor soldiers. Let's hope they received counselling after their traumatic experience. A later post by Craig is – if possible – even more shocking. Referring to his earlier article (above) he says:

"I have come to appreciate as a result of a closer reading of the biblical text that God's command to Israel was not primarily to exterminate the Canaanites but to drive them out of the land.[…] Canaan was being given over to Israel, whom God had now brought out of Egypt. If the Canaanite tribes, seeing the armies of Israel, had simply chosen to flee, no one would have been killed at all. There was no command to pursue and hunt down the Canaanite peoples.

It is therefore completely misleading to characterise God's command to Israel as a command to commit genocide. Rather it was first and foremost a command to drive the tribes out of the land and to occupy it. Only those who remained behind were to be utterly exterminated. No one had to die in this whole affair."

So, apparently it was the Canaanites' own fault for not running away. Right.

Would you shake hands with a man who could write stuff like that? Would you share a platform with him? I wouldn't, and I won't. Even if I were not engaged to be in London on the day in question, I would be proud to leave that chair in Oxford eloquently empty.

And if any of my colleagues find themselves browbeaten or inveigled into a debate with this deplorable apologist for genocide, my advice to them would be to stand up, read aloud Craig's words as quoted above, then walk out and leave him talking not just to an empty chair but, one would hope, to a rapidly emptying hall as well.