MY grandmother delighted in confounding "bad" Christians. Any chance she got, she’d skewer priests and missionaries, ministers and street preachers with relentlessly polite logic. Her concept of "bad" included both hypocrisy and ignorance.

"If they’re going to preach to me," she’d say, "then they’d better be able to give a good account of themselves." She’d make these phoney Christians squirm with the absurdities of the Bible. Dinosaurs, anyone? And she’d force them to confront the book’s cruelty. Wasn’t it nice of God to demand Abraham kill his son Isaac? But her favourite tactic was to set a trap using their own double-dealing and falsity.

Your book preaches love of the poor and fellowship with all humankind, she’d say, so why do your church leaders live in luxury; why do they heap discrimination on women and gay people; why don’t they speak out against war? Why are you in the pockets of the rich? Why don’t you overthrow the tables of the money changers? Why, most of all, don’t you truly try and live by the teachings of your Saviour, Jesus Christ, who was a great and good man?

My grandmother lost her faith slowly over decades. She’d been devout as a child and closely schooled in the Bible. She knew the book intimately. By the time I arrived, though, she was firmly atheist. My grandmother gifted me something special – she not only bred in me a healthy scepticism, she also made sure I knew my Bible back to front. She read it to me frequently. It’s one of the world’s greatest works of literature, she rightly felt. She’d tell me it was up to each person to decide whether they believed the Bible was "literal truth" or simply good stories with some decent moral messages thrown in - a bit like a version of Aesop’s Fables which someone took too seriously.

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I’ve read the Bible pretty much cover to cover twice during my life. I’m an atheist who knows the Bible, loves the Bible and can quote the Bible. I’m very comfortable with my respectful yet critical position on Christianity. There’s nothing I admire more than a Christian who walks the walk – but I've a special loathing for Christians who preach one thing and do another. Their hypocrisy repels me.

So I was confounded by the confected outrage around a tweet sent by the SNP MSP James Dornan to the Tory MP Jacob Rees-Mogg recently. Mr Rees-Mogg, who claims he’s a devout Christian, had issued a contemptible tweet about his Tory Party’s immigration policy. The new Nationality and Borders Bill will empower immigration officials to turn refugees away as they cross the sea using “reasonable force if necessary”. The Tories also plan to set up offshore "processing centres". Currently it’s an offence to aid undocumented migrants "for gain". The new law removes the words "for gain". So if you provide humanitarian assistance to someone from Iraq or Afghanistan – countries we invaded – you risk jail. Children are being sent to detention centres.

The Herald: If you believe in the Bible then you have to go all in – no ifs or butsIf you believe in the Bible then you have to go all in – no ifs or buts

Mr Rees-Mogg chose to comment on the new legislation in the tone of some monstrous Billy Bunter: “The bands of blighters bringing illegal entrants to Blighty will be broken up by this brilliant borders bill.” His tweet revealed the desert that is his soul. He has said in the past that he takes his “whip” from the church not the Conservative Whip’s Office.

Mr Dornan responded by saying Mr Rees-Mogg was “happy to see the most desperate people in the world suffer and drown. If your God exists you will undoubtedly rot in hell.” Cue screaming outrage from Conservatives. It was a masterclass in deflection. Their man Rees-Mogg was behaving abominably, so let’s find a convenient Nat as distraction.

Now, Mr Dornan has history on Twitter. Like many politicians he’s made a fool of himself online too often. Who hasn’t? That, however, doesn’t mean he’s wrong regarding Mr Rees-Mogg. Was his language a bit too brutal? Perhaps. But his logic was sound – according to Christianity.

If someone professes Christianity, and not only fails conspicuously to live up to the ideals of their faith, but also deliberately undermines the values of that faith by their actions, then not only is it acceptable to call out their hypocrisy but it’s also acceptable to ask how their God would judge them.

If you believe in the Bible then you have to go all in – no ifs or buts. Love the poor, do good works, and if you’re a rotten person you’ll rot in hell. That’s the deal, I’m afraid.

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Just read the Epistle of James in the New Testament. “What doth it profit, my brethren, though a man say he hath faith and have not works? Can faith save him? If a brother or sister be naked, and destitute of daily food, and one of you say unto them, ‘Depart in peace, be ye warmed and filled’; notwithstanding ye give them not those things which are needful to the body; what doth it profit? Even so faith, if it hath not works, is dead, being alone.”

In other words, how can you call yourself a Christian if you see someone in need but do nothing, or even worse pretend that all’s well with them. People like Mr Rees-Mogg go one step further – they don’t just pretend all is well with those in need or do nothing, they actively collude to make the suffering worse for those in need.

I'd a brief exchange with a Church of Scotland minister of my acquaintance about the Rees-Mogg-Dornan event –they’re a Christian who tries to walk the walk as best they can and I’ve a lot of respect for them. They said that Mr Rees-Mogg “needs called out on his hypocrisy as he obviously reads a different Bible to me”.

I’m an unrepentant atheist, but I know the Bible, and while Christ may love, God judges. If you profess to live by Christ’s words but act in direct contradiction to those teachings – offering pain instead of comfort – then surely your God will judge you and find you wanting. And if your god judges you, finds you wanting – if your god cannot forgive you – then isn’t rotting in hell just part of the process?

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