Then Allah says:

﴿إِلاَّ الَّذِينَ تَابُواْ مِن بَعْدِ ذَلِكَ وَأَصْلَحُواْ فَإِنَّ اللَّهَ غَفُورٌ رَّحِيمٌ ﴾

(Except those who repent thereafter and do righteous deeds; (for such) verily, Allah is Oft-Forgiving, Most Merciful.) 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 Sa`id bin Al-Musayyib -- the leader of the Tabi`in -- and also a group among the Salaf. Ash-Sha`bi 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.

﴿وَالَّذِينَ يَرْمُونَ أَزْوَجَهُمْ وَلَمْ يَكُنْ لَّهُمْ شُهَدَآءُ إِلاَّ أَنفُسُهُمْ فَشَهَـدَةُ أَحَدِهِمْ أَرْبَعُ شَهَـدَاتٍ بِاللَّهِ إِنَّهُ لَمِنَ الصَّـدِقِينَ - وَالْخَامِسَةُ أَنَّ لَعْنَةَ اللَّهِ عَلَيْهِ إِن كَانَ مِنَ الْكَـذِبِينَ - وَيَدْرَؤُاْ عَنْهَا الْعَذَابَ أَن تَشْهَدَ أَرْبَعَ شَهَادَاتٍ بِاللَّهِ إِنَّهُ لَمِنَ الْكَـذِبِينَ - وَالْخَامِسَةَ أَنَّ غَضَبَ اللَّهِ عَلَيْهَآ إِن كَانَ مِنَ الصَّـدِقِينَ - وَلَوْلاَ فَضْلُ اللَّهِ عَلَيْكُمْ وَرَحْمَتُهُ وَأَنَّ اللَّهَ تَوَّابٌ حَكِيمٌ ﴾

(6. And for those who accuse their wives, but have no witnesses except themselves, let the testimony of one of them be four testimonies by Allah that he is one of those who speak the truth.) (7. And the fifth (testimony); invoking of the curse of Allah on him if he be of those who tell a lie.) (8. But she shall avert the punishment from her, if she bears witness four times by Allah, that he is telling a lie.) (9. And the fifth; should be that the wrath of Allah be upon her if he speaks the truth.) (10. And had it not been for the grace of Allah and His mercy on you! And that Allah is the One Who forgives and accepts repentance, the All-Wise.)