Maliks Muwatta Book 41, Hadith Number 9.

Section : Stoning.

Malik related to me from Yahya ibn Said from Sulayman ibn Yasar from Abu Waqid al-Laythi that a man came to Umar ibn al-Khattab while he was in ash-Sham. He mentioned to him that he had found a man with his wife Umar sent Abu Waqid al-Laythi to the wife to question her about that. He came to her while there were women around her and mentioned to her what her husband had mentioned to Umar ibn al-Khattab, and informed her that she would not be punished on his word and began to suggest to her by that, that she should retract. She refused to retract and held firm to confession. Umar gave the order and she was stoned.