Jami at-Tirmidhi — The Book on Legal Punishments (Al-Hudud) — Hadith No: 1451
Translation
Habib bin Salim said:"A man was brought to An-Nu'man bin Bashir who had relations with the slave girl of his wife. He said: 'I give you judgement about her case according to the judgement of the Messenger of Allah (ﷺ): If she made her lawful for him, then I will lash him one hundred times, and if she did not make her lawful, then I will stone him