Al-Kāfi - Volume 7 > The Testimony of an Accuser and an Ex-convict
Hadith #4

4- وَبِهَذَا الإسْنَادِ قَالَ قَالَ أَمِيرُ الْمُؤْمِنِينَ (صَلَّى اللهُ عَلَيْهِ وَآلِه) لَيْسَ يُصِيبُ أَحَدٌ حَدّاً فَيُقَامُ عَلَيْهِ ثُمَّ يَتُوبُ إِلا جَازَتْ شَهَادَتُهُ.

4. Through the same chain of narrators as that of the previous Hadith, the following is narrated: “He (the Imam), ‘Alayhi al-Salam, has said that ’Amir al-Mu’minin, Ali, ‘Alayhi al-Salam, has said, ‘If one is subjected to penalty and he thereafter repents, his testimony becomes admissible . 555