Chavez has been praying for divine intervention during increasingly infrequent appearances on television, holding up a crucifix while vowing to overcome his illness. He says living with cancer has made him "more Christian," talk that has coincided with speculation by some Venezuelans that cancer might cut short his bid for re-election in October.
Chavez's voice cracked with emotion as he bade farewell to aides and supporters in Caracas on April 30 before leaving for what he said would be his final round of cancer treatment in Cuba.
"I'm sure our Christ will do it again, continuing making the miracle," Chavez said as he raised his cross to his lips and kissed it, prompting applause from an audience of aides.
If Chavez survives cancer, political analysts say his increasing religiosity could pay election-year dividends in a country where Catholicism remains influential.
"Given that he cannot hide the illness, but he can hide its characteristics and danger, he's decided to take as much advantage of it as he can, and one advantage is the symbolic and religious issue," said Luis Vicente Leon, a Venezuelan pollster and analyst. "He'll present himself as the chosen one, the man who has been cured and healed by the Lord to continue governing the country."
The president has alternated between emotional fragility and optimism in public, mentioning God and Jesus nearly every time he shows up on TV.
Chavez shed tears last month during a televised Mass with relatives in Venezuela, when he prayed aloud to Jesus to "give me life."
In a later appearance in Cuba, Chavez held up the same crucifix that he said helped deliver him from one of his darkest moments, a 2002 coup that briefly deposed him. He returned to the presidency within two days.
"I have great faith in what we're doing, in this intense undertaking against the illness that ambushed me last year, and I have faith, I repeat, in God," said Chavez, who looked pale and bloated.
"It's like a pact with God, with Christ my Lord," Chavez said. "I'm sure he will lay on a hand so that this treatment, which we're rigorously following, will have supreme success."
Chavez's religiosity contrasts with the resolute secularism of his political father figure, Castro, and other leaders who have followed the socialist path Chavez lauds.
A large majority of Venezuelans practice Catholicism, and Protestant denominations have grown rapidly in some parts of the country. Many Venezuelans also practice folk religions and leave offerings at roadside shrines.
Mixing religion and politics isn't new in Venezuela, even if religious groups generally don't get directly involved in politics. Former President Luis Herrera characterized himself as spiritually pure and promoted social programs for the poor while leading his Copei Social Christian party.
Other Latin American leaders have employed religious symbols while seeking votes.
Nicaraguan President Daniel Ortega highlighted his Christian faith during his re-election bid last year, when his campaign rallies were accompanied by religious processions, chants and the campaign slogan "Christian, Socialist and In Solidarity." Ortega's campaign strategy dismayed Catholic Church leaders, who called his use of spirituality part of a ploy to deceive voters.
Chavez describes himself as Catholic, but his religious beliefs are eclectic. He has at times also expressed faith in folk deities such as Maria Lionza, an indigenous goddess venerated by some Venezuelans who pay homage through candlelit rituals and shrines.
Despite his recent expressions of faith, the president has had a rocky relationship with Catholic leaders. He has accused priests of siding with the country's wealthy rather than the poor and in a particularly heated clash in 2010, suggested that Christ would whip some church leaders for lying after Cardinal Jorge Urosa warned that democratic freedoms were being eroded in Venezuela.
Chavez insists his faith goes back to his days as an altar boy, and long before his illness, he was calling Jesus Christ "the greatest socialist in history."
Still, his increasing appeals for help from Christ have shown supporters a vulnerable side to a leader who for more than 13 years in office has projected power and vigor.
"We'd forgotten for so long that Chavez is simply a man like any other, a man of flesh and blood," said Florencia Mijares, an office worker who prayed for the president at a Caracas church. "For many Venezuelans, Chavez is a savior who arrived to help everybody else and now he's the one who needs help, and many of us fear all will be lost if he dies."
Chavez has been receiving radiation therapy in Cuba over the past week, the latest phase in treatments that since June have included chemotherapy and two surgeries that removed tumors from his pelvic region, though he has not said what sort of cancer he has.
Chavez spoke by phone on Venezuelan state television on Monday, vowing to win re-election and criticizing his opponents in his first such comments since leaving Venezuela a week ago. Last week, he had instead communicated with supporters through Twitter messages.
Despite the long absences, Chavez has been leading opposition presidential candidate Henrique Capriles by double digits in recent polls.
Some of his supporters said they see Chavez's increased devotion as a natural evolution for a president in a dire situation.
As soon as Chavez revealed he had a tumor removed last year, a pro-Chavez group called the Council of Christian Public Employees organized dozens of prayer meetings across the country, several of which were broadcast live on state television and Christian radio stations.
"The president could have decided to distance himself from God or not believed in him due what he was going through," said Linda Aguirre, the organization's president. "I thank God that he's chosen the most important decision of his life: to embrace our Lord."
Indian shamans wearing parrot feathers and beads also held a healing ritual for Chavez at a Caracas plaza last month, performing traditional dances and chants, and kneeling on the ground in prayer.
"The objective is to inject the leader of the Bolivarian Revolution with positive energy," said Jesus Antonio Juagivioy, a chieftain from the president's home state of Barinas who participated in the ceremony. "We pray for his total recuperation and we know the spirits of our ancestors will help."