Sahih al-Bukhari 6827, 6828

'Ubaydullah reported that he heard Abu Hurayra and Zayd ibn Khalid say, "We were with the Messenger of Allah, may Allah bless him and grant him peace, when a man stood up and said, 'I ask you by Allah to judge between us according to the Book of Allah!' His opponent, who had more understanding than him, stood and said, 'Judge between us by the Book of Allah and give me leave to speak.' 'Speak,' he said. He said, "My son is a labourer for this man and he committed fornication with his wife. I ransomed my son with a hundred sheep and a slave-girl of mine. Then I asked the people of knowledge and they told me that my son must receive a hundred lashes and be exiled for a year and that his wife should be stoned.' The Prophet, may Allah bless him and grant him peace, said, "By the One who has my soul in His hand, I will judge between the two of you by the Book of Allah. Exalted is His renown. The sheep and servant must be returned and your son will receive a hundred lashes and be exiled for a year. Unays, go to the wife of this man and if she confesses, stone her.' He went to her and confessed and he stoned her. I said to Sufyan, "He did not say, 'They told me that my son was to be stoned'?" He said, "I am unsure about that from az-Zuhri. Sometimes I say it and sometimes I am silent about it."