Musnad Ahmad 938:21

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Qatadah, from Yunus ibn Jubayr, from Kathir ibn al-Salt, who said: Sa‘id ibn al-‘As and Zayd ibn Thabit were writing the copies of the Qur’an. They passed by this verse, and Zayd said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: "The old man and the old woman, if they commit adultery, stone them both absolutely." ‘Umar said: When it was revealed, I came to the Messenger of Allah, peace and blessings of Allah be upon him, and said: Let me write it down. Shu‘bah said: It is as if he [the Prophet] disliked that. ‘Umar said: Do you not see that the old man, if he has not been married, is flogged, and that the young man, if he commits adultery and has been married, is stoned?