Justice Mogoeng was speaking ahead of the swearing-in ceremony of several new ministers and deputy ministers, the beneficiaries of Monday evening's reshuffle.
President Cyril Ramaphosa fired 10 ministers on Monday, including former mineral resources minister Mosebenzi Zwane, former public enterprises minister Lynne Brown and Cogta minister Des van Rooyen.
In a packed room at Tuynhuys, where the swearing-in ceremony was taking place, Justice Mogoeng said he would be failing in his duty, “given our history”, if he did not underscore the significance of an oath of office.
“We're not here for a photo shoot, we're not here for a photo opportunity. We can't travel all this long way just to come gather and undertake an insignificant task.
“Everybody who is going to be called upon to take an oath or an affirmation is required to do so as allegiance to the Republic and obedience to the Constitution. So if you like, you came to enter into a formal contract with the people of South Africa,” he said.
Not far in the back of the minds of those ministers and deputy ministers seated in front of Justice Mogoeng would have been the Constitutional Court ruling in 2016.
That ruling found that then president Jacob Zuma had failed to “uphold, defend and respect” the Constitution when it ruled that the public protector's recommendations for remedial actions over Nkandla were binding.
Addressing the new members of Ramaphosa’s executive, Justice Mogoeng said: “We cannot ritualistically gather here and read out this thing as if it is inconsequential. It exists because there is good reason for its existence, otherwise it would not have found its way into our most important document as a Republic.”
He said the assumption was that people who have a measure of credibility and integrity, “and some character to write home about, are going to be presented here to the nation as those who are going to serve them, as dictated by the constitution”.
Justice Mogoeng said their new Cabinet appointees had to become servants to the people of South Africa.
“May the oath or affirmation judge, most brutally, any of us who is here for a show. Or any of us who will betray the Constitutional aspirations of the people of South Africa after having an oath or affirmation administered to him or her,” he said.
Meanwhile, Ramaphosa’s Cabinet reshuffle has drawn criticism from within the ANC-led alliance and from labour.
The ANC Youth League blasted Ramaphosa’s continued inclusion of old ministers while there were capable young people in the ANC’s national executive committee.
ANCYL national spokesperson Mlondolozi Mkhize said the current Cabinet looked like an old-age home. “This is becoming a problem because these people they keep bringing back in Cabinet are not contributing anything new there.”
Mkhize added that young and educated leaders, such as 34-year-old NEC and national working committee member Ronald Lamola, should have been included in the new cabinet.
“If the current cabinet has 35 ministers and 37 deputy ministers, why can't you have at least 10% or 20% of the total 72 members of the national executive? We can't even account for two people there,” he said.
The ANC Women’s League highlighted the reshuffle's failure to meet the 50/50 gender parity.
Ramaphosa’s Cabinet shake-up saw ANC deputy president and former Mpumalanga premier David Mabuza being elected the country’s deputy president.
Association of Mineworkers and Construction Union (Amcu) president Joseph Mathunjwa said even though it welcomed the sacking of Zwane, new minister Gwede Mantashe came with his own skeletons as he was conflicted in the mining sector.
“Already during the Farlam Commission it was pointed out that Minister Mantashe was involved in the events leading up to the Marikana massacre. Evidence showed a clear agenda to destabilise Amcu, with his open loyalty to his former trade union NUM,” Mathunjwa said.
Mathunjwa said Ramaphosa’s close relationship with Mantashe - as NUM founding leaders and current ANC national leaders, including Ramaphosa’s mining interests and his implication in the Marikana massacre - damaged the integrity of his appointment.
SA Federation of Trade Unions (Saftu) general secretary Zwelinzima Vavi said while he knew Mantashe was factional, he would do a sterling job in the Mining Ministry due to his vast knowledge about the sector.