It is Sunday morning in Randburg. Outside, it is cold, but inside, the Rhema Bible Church is buzzing. A band plays. The growing group of people entering the massive auditorium sways to and fro on its feet. A few lift their hands in the air. Everyone sings along to the words on the three big screens.

But the iconic pastor and the head of the church, Ray McCauley, is not there this morning. He is in Durban taking a break. His son, Joshua, in the same line of business, says his father is "pastor to the nation" and, as such, is "heavily involved in Mandela".

This involvement has come in the way of sermons dedicated to Madiba. Not long after Mandela went to hospital, McCauley senior said: "We as the church want him to recover and we also prayed for his family to be given strength by God during these trying times … we want him to enjoy whatever is left of his life."

He joins a large group of more populist religious leaders who have stepped forward and prayed for Mandela in front of cameras and microphones. The ANC had a truck-cum-stage decked with party flags and pictures of Mandela parked outside its Johannesburg headquarters this week, the back of which was used as an impromptu pulpit with a pastor praying for Madiba. Similar prayer meetings have been held around the country. Every organisation is making sure that it is known that it prayed for Mandela. South Africa has not seemed this religious in a long time.

And it has spread across the globe. London's Westminster Abbey has been holding daily prayers for Mandela. A special prayer has been written, calling on God to "look with mercy on Madiba Mandela and on all your children in South Africa".

It has also let it be known that it is considering holding a memorial for the elder statesman at the abbey, the first time this would be done for a non-Briton.

'Why do you think he is still alive?'
The one public religious figure to have visited Mandela and to have shied away from making public pronouncements is Thabo Makgoba, the Anglican archbishop of Cape Town. He visited Madiba's bedside at Mediclinic Heart Hospital in Pretoria, and prayed with the family. Parts of it were released on the church's website, asking God to "guide the medical staff so that they may know how to use their skills wisely and well in caring for Madiba and keeping him comfortable".

The quiet hopes of Mokgoba are echoed outside Rhema Church on Sunday. A few people, dressed in their best clothes and carrying blankets to donate, say they have come to pray for Mandela.

"We must come together and pray because God will listen if we all pray," says one man, holding a small child in each hand.

"We must do everything we can for Mandela," he says, before entering the church.

Following him inside, Fashion Sangwisi insists that Mandela was religious. "All the time in prison, God was with him. He is always there when people ask for help. So when we pray for Madiba to be better, he listens to us. I know so many people who are praying. Why do you think he is still alive?"

Closer to the Pretoria hospital, the people interviewed all say they have prayed for his health.

Prayers and hope
"He gave us 27 years, so we pray for him to have some more time," says Hector Ravele. He does not trust the information being given by any source and feels powerless.

"What can we do except pray? We do not know how he is and we can't talk to anybody so all we have is our prayers and hope."

A few others walking past the hospital say they pray because it makes them feel as though they are helping in their own way.

"All we can do is pray. We love Tata Madiba and we want him to stay, so we ask God to make him better," says Fundile Tshepiso. He prays at home and at church. "We pray for his doctors … and look, he has fought for so many weeks."

Their prayers are mostly for Mandela to get better. Few say they are willing to let him go.

"I pray for him to be comfortable," says Mpho Lebepe. "Maybe it is time to let him sleep. Tata is tired from all he has done for us."

Worries
A Pretoria pastor, who does not want to speak in public and therefore prefers not to be named, says it is not the role of pastors to stand in front of cameras and pray. Theirs is a duty to God and to their parishioners.

"Your prayers to God are private, especially when you are praying for a loved one, which Mandela is for many people," says the pastor. He does not name anyone, but says populist religious figureheads are taking advantage of the needs of their flock to be in the spotlight.

The pastor has mentioned Mandela in sermons, but only to say that people should pray for him, and all the other people who need help.

"People do not know how to handle their emotions. For older people, Mandela feels like family, but they can't go to him like you normally would. The next choice is prayer."

In the past month, people have approached him with their worries about Mandela. Many do not know if it is right to pray for him to get better, or if they should pray for him to go in peace.

"They ask if their prayers help, and if it is wrong to pray for him to stay alive if he is in pain."

His own prayer is simple: "I pray that he is comfortable, and I pray for his family, especially Graça [Machel, Mandela's wife, who has been at his side the whole time]."

Religion kept out of politics

Nelson Mandela's religious views are not easily discernible. He was baptised a Methodist, and many in his family were Jehovah's Witnesses. But he has always kept his religion – if any – private, save when he said his 27 years in prison had given him "time to think" about religion.

In March, the official Mandela Twitter account, run by the Nelson Mandela Centre of Memory, posted another rare quote of his on religion: "Always make religion a private and personal affair confined to yourself."

Unlike President Jacob Zuma, he stayed away from including religion in his state functions and addresses.

He has, however, praised religious institutions for the help they gave the anti-apartheid struggle. In a 1999 speech to the Parliament of the World's Religions, which was gathering in Cape Town, he said: "In our country, my generation is the product of religious education … Without the church, without religious institutions, I would never have been here today."

This was because churches were often the only source of good schooling in black areas. Religious groups also helped to educate prisoners and looked after their families while they were behind bars.

 In an interview with American broadcast network PBS in 1999, Archbishop Desmond Tutu said that, when it came to religion, Mandela was "a very secret person". He refused to use it as a political tool – something that would have brought him great support.

"We should respect the fact that he refused to manipulate religion in that way," he said.