This Ayah states the prescribed punishment for making false accusations against chaste women, i.e., those who are free, adult and chaste. If the person who is falsely accused is a man, the same punishment of flogging also applies. If the accuser produces evidence that what he is saying is true, then the punishment does not apply. Allah said:

If the accuser cannot prove that what he is saying is true, then three rulings apply to him: (firstly) that he should be flogged with eighty stripes, (secondly) that his testimony should be rejected forever, and (thirdly) that he should be labelled as a rebellious who is not of good character, whether in the sight of Allah or of mankind.

Explaining the Repentance of the One Who makes a False Accusation

Then Allah says:

This exception refers to the second and third rulings mentioned above. The flogging has been carried out regardless of whether he repents or persists, and after that there is no further punishment, as is agreed among the scholars. If he repents, then his testimony may be accepted, and he is no longer to be regarded as a rebellious. This was the view of Said bin Al-Musayyib - the leader of the Tabi'in - and also a group among the Salaf.

Ash-Shafii and Ad-Dahhak said, “His testimony cannot be accepted even if he does repent, unless he himself admits that he said something false, in which case his testimony may be accepted.” And Allah knows best.