Mishkat al-Masabih 3557
‘Umar said:
God sent Muhammad with the truth and sent down the Book to him, and the verse of stoning was included in what God most high sent down. God's Messenger had people stoned to death and we have done it also since his death. Stoning is a duty laid down in God’s Book for married men and women who commit fornication when proof is established, or if there is pregnancy, or a confession. 

(Bukhari and Muslim.)
وَعَنْ عُمَرَ رَضِيَ اللَّهُ عَنْهُ قَالَ: إِن الله بعث مُحَمَّدًا وَأَنْزَلَ عَلَيْهِ الْكِتَابَ فَكَانَ مِمَّا أَنْزَلَ اللَّهُ تَعَالَى آيَةُ الرَّجْمِ رَجَمَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَرَجَمْنَا بَعْدَهُ وَالرَّجْمُ فِي كِتَابِ اللَّهِ حَقٌّ عَلَى مَنْ زَنَى إِذَا أُحْصِنَ مِنَ الرِّجَالِ وَالنِّسَاءِ إِذَا قَامَتِ الْبَيِّنَةُ أَوْ كانَ الحَبَلُ أَو الِاعْتِرَاف