United Democratic Movement MP Nqabayomzi Kwankwa informed MPs of the threat, reading out the SMS message the journalist received.
"Traitors protecting your white friends in Parliament who started this, telling lies about your comrades. You are warned, we don't kill blacks but sit and watch the blood flow," the SMS said, according to Kwankwa.
The journalist was not identified.
On Monday journalists Thembeka Gqubule, Krivani Pillay, Lukhanyo Calata and Vuyo Mvoko gave harrowing testimony about Hlaudi Motsoeneng, the man who went from an ordinary producer for a Free State current affairs show to top management at the broadcaster.
The journalists were among eight fired earlier this year for objecting openly to censorship as well as the manipulation and distortion of news.
Most have been reinstated. Motsoeneng, the journalists said, had wrought a "reign of terror" over the newsroom, insisting on news policies which included the banning footage of violent service delivery protests, a decision the Independent Communications Authority of South Africa later ordered the broadcaster to rescind.