Speaking mainly in isiZulu, Zuma said he would be active at his branch once he leaves office. "I want to tell you now, my friends that if you tell me to step down tomorrow, I will... I will remain an ANC member until I die," said Zuma.
"There is a short period left until I finish the task I was given by the ANC. A new president will come in in December, elected by the ANC. Even if you say I must leave, I will leave with a clear heart. I'll be ANC until I die and do work without a salary because I'll be getting pension... I'll work hard, be there and use my strength to debate."
Zuma, who has come under fire from opposition parties and ANC alliance partners, hit back at his detractors who had earlier converged in Pretoria and marched against him. He said that "the new trend" from opposition parties was to take him to court at every turn.
"They are troubled, I feel sorry for them... if I sneeze or cough now it will be headlines tomorrow and they will ask me to step down."
The opposition parties would never be satisfied even if the ANC elected a new leader, he said.
Leaders who joined the celebrations included Zuma's staunch supporters such as ANC deputy secretary-general Jessie Duarte, Congress of South African Trade Unions (Cosatu) president Sidumo Dlamini, Umkhonto we Sizwe Military Veterans Association (MKMVA) chairman Kebby Maphatsoe, ANC Youth League leaders, ANC Women's League leaders led by its president Bathabile Dlamini and North West premier Supra Mahumapelo.
Party secretary-general Gwede Mantashe, treasurer Zweli Mkhize and Deputy President Cyril Ramaphosa were noticeably absent at the event.
ANCWL president, Dlamini, wished Zuma well, and told him the ANC would always defend him. She lashed out at "people who stole the land and now claimed the ANC was led by thieves".
"They're scared. They have gone out there as if there is a war... we have always indicated as the women's league that you will finish your term. You are firm, we are led by a strong leader indeed."
The Cosatu president, whose organisation has joined the calls demanding that Zuma step down, urged the President to "remain strong during the trying times".
"Once they stand and mention your name, rain falls. Personally, I need you to be strong," said Dlamini.
Zuma presented the family of Ontlametse Phalatse, the country's only Progeria sufferer who died early on Wednesday, with a car.
He had spent a day, two weeks ago with Phalatse for her 18th birthday. The vehicle was bought by the Jacob Zuma Foundation, said the President.
The foundation's chairwoman and Dudu Myeni was at hand to deliver the keys to the vehicle.
Phalatse's wish was to see her family living in a descend house and having a car. The family had been invited as guests at Zuma's birthday.