Godliness is the latest political battleground in the Republican presidential primary season, with the two front-runners' campaigns in South Carolina pummeling each other over their Christian faiths.

Donald Trump, the billionaire real estate developer who captured Tuesday's New Hampshire primary in sweeping fashion, asked early Friday morning on Twitter: 'How can Ted Cruz be an Evangelical Christian when he lies so much and is so dishonest?'

That slap, a reference to ongoing spats over anti-Trump 'push polls' and claims about Trump's stance on gay marriage, came after radio host Glenn Beck – a key Cruz supporter in the evangelical deep south – said Trump is a 'very dangerous' fake Christian.

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FINGER-POINTING: Ted Cruz claimed Thursday night at a South Carolina church that Donald Trump has 'gone soft' on gay marriage as his endorser Glenn Beck of talk radio fame blasted the billionaire as a fake Christian

PODIUM, NOT PULPIT: Trump doesn't make religion a major part of his sales pitch but has been known to bring his childhood Bible to rallies in evangelical-heavy regions of the country

TWEET-STORM: Trump said online that Ted Cruz is a liar

'Too many people right now are looking like a guy like Donald Trump and believing that that man has ever opened a Bible,' he told a crowd at Morningstar Fellowship Church in Fort Mill, South Carolina. 'That's the biggest crock of bullcr*p I've ever heard! We all know it!'

'But there's too many people who want just to go along for the show. This isn't a show! This is a profoundly sacred responsibility, and each one of us will be held accountable by our creator when we meet him.'

'Donald Trump is very dangerous, in my opinion,' Beck said.

Cruz, a Texas senator, is facing new questions about his own Bible-thumping habits after his campaign released – and then quickly retracted – an ad attacking Florida Sen. Marco Rubio.

The reason: A softcore pornographic actress had a role in the 30-second spot.

But whatever self-inflicted moral wounds Cruz may suffer, his religious fervor remains a central part of his campaign. He has made more campaign appearances in churches than anyone else in the GOP field so far.

And on Thursday, hours before his porn-star video kerfuffle erupted, he spoke at the Carolina Values Summit, an annual gathering of Christian right voters.

SWINGING BACK: This tweet from Trump followed Cruz's claim that he has 'gone soft' on gay marriage

CHURCHY: Cruz has held more campaign events in Christian houses of worship than any other Republican 2016 presidential candidate

Cruz said there that his top Republican rivals have 'gone soft' on Christian morality – especially the thorny issue of same-sex marriage.

And he said two in particular – thought to mean Rubio and Trump – have acknowledged that a 2015 Supreme Court ruling on the subject is now 'the law of the land.'

Cruz, however, predicted that the decision 'will not stand.'

'There is something profoundly wrong when Republican presidential candidates are repeating Barack Obama’s talking points on gay marriage, saying "we surrender, we give up",' Cruz said.

'You might as well light the White House up in rainbow colors.'

Referring to that statement, Trump tweeted about 'lying Cruz,' asking if he is 'the worst liar, crazy or very dishonest. Perhaps all 3?'

Meanwhile Ben Carson, who is languishing at the bottom of the GOP leader board as it condenses to fewer and fewer candidates, said Friday morning that he has forgiven Cruz for his campaign's 'despicable' efforts to spread a rumor in Iowa that he was quitting the race.

'It's a question of character,' Carson said on MSNBC's 'Morning Joe' program.

'Character is also indicated by the kind of people that you protect and that you surround yourself with. And you know, the situation in Iowa, you know, I'm willing to forgive Ted Cruz. You know, he said that he didn't know that that was going on.'

SOUTH CAROLINA, WE HAVE AN IMAGE PROBLEM: Amy Lindsay, whose acting resume includes work in softcore adult films, was cast in a Cruz ad that hammered Marco Rubio

CAMPAIGN TRAIL: While Cruz was in South Carolina, whose GOP primary is on Feb. 20, Trump was speaking to more than 13,500 people in Baton Rouge, Louisiana, more than three weeks ahead of the March 5 primary there

Asked what he would do if his campaign failed to catch fire in South Carolina, Carson said 'I believe we're gonna do extraordinarily well here,' but 'I reassess the future of the campaign every day.'

'It's a long race. It's a nine-inning game, we don't call it after the second inning,' he said. 'We're going to do just fine and I think South Carolina will be the turning point.'

While Cruz has Beck and other surrogates questioning the religious bona fides of his opponents, he insists he's not trying to position himself as a Jesus freak.

'I am a Christian and the Word says if you are ashamed of Jesus He will be ashamed of you. I don’t intend to have that conversation with my maker. It is an integral part of who I am my faith,' he told 'The Brody File' on the Christian Broadcasting Network on Friday.