Saeed bin Jubair (may Allah have mercy on him) narrates: I was asked about those who perform li'an (mutual cursing) — whether separation should be enforced between them or not. This was during the governorship of Abdullah bin Zubair (may Allah be pleased with them both). I did not know what answer to give, so I stood up from my place and went towards the house of Ibn Umar (may Allah be pleased with them both). I met him and said: O Abu Abdur Rahman! Should separation be enforced between those who perform li'an? He said: Subhan Allah! How astonishing! This question was first asked by so-and-so, the son of so-and-so. He said: O Messenger of Allah! Tell me, if a man sees his wife committing indecency, if he speaks, it is a very grave and unpleasant matter, and if he remains silent, the matter is also very serious. The Prophet (peace and blessings be upon him) did not give him any answer. After some time, he came to the Prophet (peace and blessings be upon him) and said: The hypothetical question I asked has now actually happened to me. So Allah Almighty revealed these verses of Surah An-Nur: {وَالَّذِینَ یَرْمُونَ أَزْوَاجَہُمْ … … أَنَّ غَضَبَ اللّٰہِ عَلَیْہَا إِنْ کَانَ مِنْ الصَّادِقِینَ۔} … Those who accuse their wives … if he is truthful, then Allah's wrath descends upon that woman. The Prophet (peace and blessings be upon him) began the li'an with the man, admonished and reminded him, and informed him that the punishment of this world is much lighter than the punishment of the Hereafter. The man said: By the One Who sent you with the truth, I have not lied to you. After that, the woman was admonished and reminded, and she was warned that the punishment of this world is lighter than that of the Hereafter. The woman also said: By the One Who gave you the truth, he is lying. The man began, he testified four times that he was truthful, and the fifth time he said: May the curse of Allah be upon me if I am lying. Then after that, the woman, in the name of Allah, testified four times that he is among the liars, and the fifth time she said: May the wrath of Allah be upon me if he is truthful. Then the Prophet (peace and blessings be upon him) enforced separation between the two.