حَدَّثَنِي مَالِكٌ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ بْنِ عُتْبَةَ بْنِ مَسْعُودٍ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّهُ قَالَ سَمِعْتُ عُمَرَ بْنَ الْخَطَّابِ، يَقُولُ الرَّجْمُ فِي كِتَابِ اللَّهِ حَقٌّ عَلَى مَنْ زَنَى مِنَ الرِّجَالِ وَالنِّسَاءِ إِذَا أُحْصِنَ إِذَا قَامَتِ الْبَيِّنَةُ أَوْ كَانَ الْحَبَلُ أَوْ الاِعْتِرَافُ ‏.‏

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.' " Translation Not Available

Book Ref: Muwatta Imam Malik Book 41 Hadith 1510
Web Ref:  Muwatta Imam Malik Book 41 Hadith 8