Under fire Public Protector Busisiwe Mkhwebane and constitutional law expert Professor Pierre De Vos have exchanged quippy barbs on Twitter over her position and their respective understandings of the law.Mkhwebane's fitness to hold office is currently under scrutiny, with various sectors calling for Parliament to expedite an inquiry into her fitness to hold the office.De Vos, who has been critical of some of Mkhwebane's high-profile reports, commented on her recent visit to a KwaMhlanga prayer session for strength in her incumbent role."If the particular God being prayed to here is keen on the facts and the law, this is not going to be of any help," De Vos tweeted.A seemingly annoyed Mkhwebane hit back, saying the constitutional law expert should "prepare and sharpen" himself to be the next Public Protector, having initially been shortlisted for the same post that Mkhwebane eventually won."If you going to mock me because of my belief which is enshrined in the constitution you claim to be an expert on, at least respect people who are Christians (sic)," she continued.If the particular God being prayed to here is keen on the facts and the law, this is not going to be of any help. https://t.co/O4DiBLzbpa— Pierre de Vos (@pierredevos) August 30, 2019 Perhaps you need to sharpen and equip yourself to be the next PP since you were not successful in the shortlisting.If you going to mock me because of my belief which is enshrined in the constitution you claim to be an expert on, at least respect people who are Christians https://t.co/IYBYo0yo7r— Adv Busisiwe Mkhwebane (@AdvBMkhwebane) August 31, 2019 To that, De Vos retorted:"It's water under the bridge now for Public Protector reports already concluded, but I wish you all the best in getting the law and the facts right in future investigations."It's water under the bridge now for Public Protector reports already concluded, but I wish you all the best in getting the law and the facts right in future investigations. https://t.co/4VZMVDJ9QX— Pierre de Vos (@pierredevos) August 31, 2019 EXPLAINED: 5 questions answered on Parliament's process against the Public ProtectorA user @MagaselaMzobe then asked De Vos if he regarded any recent decision of Mkhwebane's as a good one.He replied yes, that her decision to drop her recent appeal to the ConCourt was a "wise and good" one.Prayer sessionDuring the prayer session in Mpumalanga, which was attended by politicians including ANC Women's League president, Bathabile Damini, Mkhwebane said there were people and organisations gunning for her head, News24 reported.READ: 'They may remove me from office, but I will always know the truth'Mkhwebane said she would always know the truth even if they succeeded. Her and her team were doing their work without fear and favour, she said.Dlamini said Mkhwebane's predecessors did not face the backlash that she was currently receiving.Dlamini took a swipe at some South African female judges, who she claimed thought they "flew" into occupying their positions.The process meanwhile to look into the steps to remove the head of a Chapter Nine institution, like the Public Protector, took a step forward after being referred to Parliament's rules committee this past week.This after the DA's chief whip John Steenhuisen asked Parliament to review Mkhwebane's fitness to hold office for the third time following a number of high-profile court judgments against her.