Why Register for an Income Tax Number

I earn R6000.00 a month. My employer told me that everybody has to register and have a tax number, regardless if you earn under the threshold and don't pay tax. What's the reason that we all have to register for an income tax number, is this correct?

Yes, your employer is correct as they're required to reconcile their income to SARS twice a year and each employee needs a tax number for them to be able to submit the reconciliation to SARS.