(CNN) -- For the first time in 14 years, Hugo Chavez isn't running for president in Venezuela.
But his legacy has loomed large over weeks of intense campaigning. And his words still echo through the South American country -- literally.
At rallies, a recording of Chavez's voice belting out the national anthem booms through loudspeakers. A phrase Chavez used has become a campaign slogan for Nicolas Maduro, the man Chavez tapped to be his successor.
Thursday was no exception. State-run VTV aired video of Maduro waving to supporters at a Caracas rally marking the end of his campaign. His official campaign theme song blared in the background.
The song -- "Maduro from my heart" -- begins with Chavez's voice, endorsing Maduro's candidacy,
The catchy tune includes lyrics like "with Chavez and Maduro the people are safe," "Chavez forever, Maduro for president" and "Chavez, I swear to you, my vote is for Maduro."
Less than six weeks after Chavez's death, Venezuelans head to the polls Sunday to pick a new leader.
Maduro, a member of Chavez's inner circle during his 14-year rule, has pledged to continue Chavez's efforts to build "21st century socialism."
Opposition candidate Henrique Capriles Radonski says he is pushing a more moderate approach, promising to continue social programs and improve the country's economy.
Both candidates closed their campaigns with massive rallies on Thursday, vowing to win decisive victories in Sunday's election.
Before Maduro spoke to supporters, a large screen behind him showed videos of Chavez on the campaign trail last year, dancing alongside supporters and singing the national anthem.
Members of Chavez's family surrounded Maduro onstage, hugging him and pumping their fists in support.
When he registered to run for the presidency, Maduro told supporters, "I am not Chavez, but I am his son."
At one rally, he told supporters that Chavez appeared to him in the form of a little bird to give him spiritual support.
The frequent references to Chavez have drawn criticism from many in the opposition.
One opposition website alleges that Maduro has said Chavez's name more than 7,000 times in public appearances since the president's death on March 5.
"In recent days they were talking about a little bird, and I said, my God, with so many problems that there are in Venezuela, we have someone who believes in little birds," Capriles said at a recent rally.
Capriles has criticized Maduro for invoking Chavez since the outset of the campaign.
"Make no mistake, Nicolas," Capriles said at a rally with supporters last month, "do not hide behind the image of the president. Let him rest in peace."
While opposition figures have mocked Maduro's recent reference to the bird, Maduro and his supporters have embraced it. VTV showed a bird perched on Maduro's shoulders at the outset of Thursday's rally.
Maduro has said he's proud to continue "Chavismo," the political movement Chavez started.
Throngs of dedicated followers still call themselves Chavistas in devotion to the former president. Some analysts have questioned whether Maduro will have the charisma to maintain their support.
At Capriles' campaign closing rally on Thursday, one supporter waved a large sign above the crowd. "I was a Chavista," it said. "Now I am a Caprilista."
Maduro told supporters on Thursday that Chavez remains at the helm.
"This is Chavez's post," Maduro said, gesturing toward the lectern where he stood. "Chavez is still leading with his example and his love."
CNN's Rafael Romo contributed to this report.