Malik related to me from Ibn Shihab from Ubaydullah ibn Abdullahibn 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 commitadultery, men or women when they are muhsan and when there is clearproof of pregnancy or a confession.' "
USC-MSA web (English) reference: Book 41, Hadith 8
Arabic reference: Book 41, Hadith 1510