Al-Kāfi - Volume 7 > The Testimony of an Accuser and an Ex-convict
Hadith #2

2- أَحْمَدُ بْنُ مُحَمَّدٍ عَنِ الْحُسَيْنِ بْنِ سَعِيدٍ عَنِ النَّضْرِ بْنِ سُوَيْدٍ وَحَمَّادٍ عَنِ الْقَاسِمِ بْنِ سُلَيْمَانَ قَالَ سَأَلْتُ أَبَا عَبْدِ اللهِ (عَلَيْهِ السَّلام) عَنِ الرَّجُلِ يَقْذِفُ الرَّجُلَ فَيُجْلَدُ حَدّاً ثُمَّ يَتُوبُ وَلا يُعْلَمُ مِنْهُ إِلا خَيْراً أَتَجُوزُ شَهَادَتُهُ قَالَ نَعَمْ مَا يُقَالُ عِنْدَكُمْ قُلْتُ يَقُولُونَ تَوْبَتُهُ فِيمَا بَيْنَهُ وَبَيْنَ اللهِ وَلا تُقْبَلُ شَهَادَتُهُ أَبَداً فَقَالَ بِئْسَ مَا قَالُوا كَانَ أَبِي يَقُولُ إِذَا تَابَ وَلَمْ يُعْلَمْ مِنْهُ إِلا خَيْراً جَازَتْ شَهَادَتُهُ.

2. Ahmad ibn Muhammad has narrated from al-Husayn ibn Sa‘id from al-Nadr ibn Suwayd and Hammad from al-Qasim ibn Sulayman who has narrated the following: “I once asked abu ‘Abd Allah, ‘Alayhi al-Salam, about the case of a man who accuses a man, then he is whipped as penalty then he repents and nothing but good is seen from him; if his testimony is acceptable. He (the Imam) said, ‘Yes, it is acceptable. What do people in your area say about it ? 5 I replied, ‘They say that his repentance is between him and Allah but his testimony is never acceptable . 5 He (the Imam) said, ‘What they say is bad. My father would say that if he repents and nothing but good is seen from him his testimony is acceptable . 555