Imam Malik, may Allah have mercy on him, said: If a person confesses to adultery, and then afterwards denies it and says: I did not commit adultery, rather I did such-and-such an act (for example, had intercourse with my wife during her menstruation, and considered it adultery), then the hadd punishment will not be carried out on him, because for the hadd punishment to be carried out, either there must be just witnesses or a confession upon which he remains firm until the hadd is carried out.
It is narrated from Safiyyah bint Abi Ubaid that people brought a man to Sayyiduna Abu Bakr Siddiq (may Allah be pleased with him) who had committed fornication with a virgin slave girl and made her pregnant. Afterwards, he confessed to the fornication, and he was not a muhsan (i.e., not married). Sayyiduna Abu Bakr (may Allah be pleased with him) ordered that he be flogged, so the prescribed punishment was carried out on him. After that, he was sent away towards Fadak (Fadak is a place two days' journey from Madinah).
Hadith Referenceموطا امام مالك رواية يحييٰ / كتاب الحدود / 1553
Hadith Gradingمحدثین:موقوف ضعيف
Hadith Takhrij«موقوف ضعيف، وأخرجه البيهقي فى«سننه الكبير» برقم: 17073، 17074، والبيهقي فى«سننه الصغير» برقم: 3219، والبيهقي فى «معرفة السنن والآثار» برقم: 5060، وعبد الرزاق فى «مصنفه» برقم: 13311، 13312، وابن أبى شيبة فى «مصنفه» برقم: 29392، فواد عبدالباقي نمبر: 41 - كِتَابُ الْحُدُودِ-ح: 13»