It reached Malik that Sa'id bin al-Musayyib and Sulayman bin Yasar (may Allah have mercy on them) were asked about a man who had been given the hadd punishment: is his testimony permissible? They said: Yes, if his repentance becomes evident. And Ibn Shihab was asked about a man who has been given the hadd punishment by flogging: is his testimony permissible? He said: Yes, if his repentance becomes evident.
Imam Malik (may Allah have mercy on him) said: This is the position with us: "Except those who repent after that and reform, then Allah is Most Forgiving, Most Merciful" [Surah Al Imran: 89]. If the one who has been given the hadd punishment repents, his testimony is acceptable.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20556