Muwatta Malik
Hadith #1507
Malik related to me from Ibn Shihab from Ubaydullah ibn Abdullah ibn Utba ibn Masud that Abdullah ibn Abbas said, ""I heard Umar ibn al- Khattab say, 'Stoning is in the Book of Allah for those who commit adultery, men or women when they are muhsan and when there is clear proof of pregnancy or a confession