Muwatta Malik 1503
Hudud
حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، أَنَّهُ أَخْبَرَهُ . أَنَّ رَجُلاً اعْتَرَفَ عَلَى نَفْسِهِ بِالزِّنَا عَلَى عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَشَهِدَ عَلَى نَفْسِهِ أَرْبَعَ مَرَّاتٍ فَأَمَرَ بِهِ رَسُولُ اللَّهِ صلى الله عليه وسلم فَرُجِمَ . قَالَ ابْنُ شِهَابٍ فَمِنْ أَجْلِ ذَلِكَ يُؤْخَذُ الرَّجُلُ بِاعْتِرَافِهِ عَلَى نَفْسِهِ
Malik related to me that Ibn Shihab informed him that a man confessed that he had committed adultery in the time of the Messenger of Allah, may Allah bless him and grant him peace, and he testified against himself four times, so the Messenger of Allah, may Allah bless him and grant him peace, gave the order and he was stoned. Ibn Shihab said, "Because of this a man is to be taken for his own confession against himself
Grading: Salim al-Hilali: Sahih
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.