Donald Trump likes to tell anyone who will listen just how much he loves God and how important faith is to him.

Yet, when he went to church over the weekend in Iowa, the Republican frontrunner made a slip that triggered some to question just how frequently he attends such services.

At the nondenominational First Christian Church, in Council Bluffs, Mr Trump reportedly mistook the silver Communion plates that were passed around as the offering plates and dug out some dollar bills from his pocket.

Mr Trump received the backing of Jerry Falwell Jr (AP)

“I thought it was for offering,” he told his staff members, according to the Associated Press. He later placed some notes in the offering plate, or offertory.

Mr Trump has been working hard to reach out and court the support of evangelical Christians as he makes his bid for the White House. Last month, he spoke at the the Christian Liberty University, only to fluff a bible reference.

On Saturday, Mr Trump appeared with the president of the university, Jerry Falwell JR, whose late father was an influential preacher and Christian activist, at a campaign rally in Davenport.

Mr Trump said that Mr Falwell, who has endorsed him for president, had helped him reach out to Christians and claimed that his position as Republican frontrunner on the eve of the caucuses had been secured by the support of evangelicals.

On Saturday, Mr Trump also released a new video showing off the Trump family Bible, saying it is “very special to me.”

In the video, Mr Trump holds up mother’s bible to the camera, pointing to one of the early pages.

“In fact, it’s her writing, right here. She wrote the name and the address, and it’s just very special to me,” he says.

He ends by saying: “And, again, I want to thank the evangelicals. I will never let you down,” he said.

Despite such appeals, and Mr Falwell’s endorsement, many have continued to question whether Mr Trump’s purported embrace of religion is anything more than political convenience.

Last summer, Mr Trump spoke about taking part in in communion, when he talked to CNN.

“When I drink my little wine - which is about the only wine I drink - and have my little cracker, I guess that is a form of asking for forgiveness, and I do that as often as possible because I feel cleansed,” he said. “I think in terms of ‘Let’s go on and let’s make it right’.”

He also raised eyebrows among some evangelicals by declining to identify his favourite bible verse, saying that it was “very personal” to him.