Abdullah b. 'Abbas reported that 'Umar b. Khattab sat on the pulpit of Allah's Messenger (may peace be upon him) and said: Verily Allah sent Muhammad (may peace be upon him) with truth and He sent down the Book upon him, and the verse of stoning was included in what was sent down to him. We recited it, retained it in our memory and understood it. Allah's Messenger (may peace be upon him) awarded the punishment of stoning to death (to the married adulterer and adulteress) and, after him, we also awarded the punishment of stoning, I am afraid that with the lapse of time, the people (may forget it) and may say: We do not find the punishment of stoning in the Book of Allah, and thus go astray by abandoning this duty prescribed by Allah. Stoning is a duty laid down in Allah's Book for married men and women who commit adultery when proof is established, or it there is pregnancy, or a confession.
Sahih Muslim 17:4194


[Narrated 'Aisha] "The verse of the stoning and of suckling an adult ten times were revealed, and they were (written) on a paper and kept under my bed. When the messenger of Allah expired and we were preoccupied with his death, a goat entered and ate away the paper."
Musnad Ahmad bin Hanbal. vol. 6. p. 269; Sunan Ibn Majah, p. 626; Ibn Qutbah, Tawil Mukhtalafi 'l-Hadith (Cairo: Maktaba al-Kulliyat al-Azhariyya. 1966) p. 310; As-Suyuti, ad-Durru 'l-Manthur, vol. 2. p. 13