Musannaf Ibn Abi Shayba 18:1159

Abu Bakr narrated to us, he said: 'Abdah narrated to us, from al-A'mash, from Ibrahim, from 'Alqama, from 'Abdullah, who said: While we were one night in the mosque, a man came and said: "If a man were to find a man with his wife and killed him, would you kill him? Or if he spoke of it, would you flog him? I will certainly mention this to the Prophet, may Allah bless him and grant him peace." So he came to him and mentioned that, and he (the Prophet) remained silent regarding him. Then the verse of *Li'an* (imprecation) was revealed. The Prophet, may Allah bless him and grant him peace, called him and recited it to him. Later, the man came accusing his wife, so the Prophet, may Allah bless him and grant him peace, performed the *Li'an* between them and said: "It is possible that she will bring him forth black and curly-haired." And she brought him forth black and curly-haired.