Narrated Sa'eed bin Jubair:
"I was asked about those who were involved in the case of Li'an and if they are to be separated, during the leadership of Mus'ab bin Az-Zubair. I did not know what to say. So I went to the house of 'Abdullah bin 'Umar and I sought permission to enter. I was told he was taking a nap, but he heard me taking and he said: 'Is it Ibn Jubair? Enter. You would not have come except for a need.'" He said: "So I entered and found him laying on a saddlecloth from his mount. I said: 'O Abu 'Abdur-Rahman! Are those involved in Li'an separated?' He said: 'Glorious is Allah! Yes. The first who asked about hat was so-and-so the son of so-and-so. He came to the Prophet (ﷺ) and said "O Messenger of Allah! If one of us saw his wife committing adultery, what should he do? If he were to say anything, his statement would be a horrible matter, and if he were to remain silent, his silence about the matter would be horrible." He said: 'So the Prophet (ﷺ) remained silent and did not answer him. Afterwards he came to the Prophet (ﷺ) and said: "The one who asked you about it has been tried by it." So Allah revealed these Ayat from Surat An-Nur: 'And those who accuse their wives and have no witnesses except themselves, let the testimony of one of them be four testimonies by Allah (24:6-10)' - until the end of those Ayat. He said: 'So he called for the man and recited the Ayat to him and admonished him, reminded him, and he told him: "Indeed the punishment of the world is less than the punishment of the Hereafter." So he said: "Nay! By the One Who sent you with the Truth! I did not lie about her." Then he (ﷺ) did the same with the woman, admonishing her and reminding her and he told her: "Indeed the punishment of the world is less than the punishment of the Hereafter." She said: "Nay! By the One Who sent you with the Truth! He is not telling the truth.'" "He said: 'So he started with the man: He testified four times, by Allah that he is one of the truthful, and the fifth time that the curse of Allah be upon him if he was one of the liars. Then the same with the woman: She testified four times by Allah, that he was one of the liars, and the fifth time that the wrath of Allah be upon her if he was one of the truthful. Then he separated the two of them.'"
English reference: Vol. 5, Book 44, Hadith 3178
Arabic reference: Book 47, Hadith 3478