Sahih al-Bukhari Book 68, Hadith 61
I asked Ibn `Umar about those who were involved in a case of Lien. He said, "The Prophet (ﷺ) said to
those who were involved in a case of Lien, 'Your accounts are with Allah. One of you two is a liar,
and you (the husband) have no right over her (she is divorced)." The man said, 'What about my
property (Mahr) ?' The Prophet (ﷺ) said, 'You have no right to get back your property. If you have told the
truth about her then your property was for the consummation of your marriage with her; and if you
told a lie about her, then you are less rightful to get your property back.' " Sufyan, a sub-narrator said:
I learned the Hadith from `Amr. Narrated Aiyub: I heard Sa`id bin Jubair saying, "I asked Ibn `Umar,
'If a man (accuses his wife for an illegal sexual intercourse and) carries out the process of Lian (what
will happen)?' Ibn `Umar set two of his fingers apart. (Sufyan set his index finger and middle finger
apart.) Ibn `Umar said, 'The Prophet (ﷺ) separated the couple of Bani Al-Ajlan by divorce and said thrice,
"Allah knows that one of you two is a liar; so will one of you repent (to Allah)?' "
I asked Ibn `Umar, "(What is the verdict if) a man accuses his wife of illegal sexual intercourse?" Ibn `Umar said, "The Prophet (ﷺ) separated (by divorce) the couple of Bani Al-Ajlan, and said, (to them), 'Allah knows that one of you two is a liar; so will one of you repent?' But both of them refused. He again said, 'Allah knows that one of you two is a liar; so will one of you repent?' But both of them refused. So he separated them by divorce." (Aiyub, a sub-narrator said: `Amr bin Dinar said to me, "There is something else in this Hadith which you have not mentioned. It goes thus: The man said, 'What about my money (i.e. the Mahr that I have given to my wife)?' It was said, 'You have no right to restore any money, for if you have spoken the truth (as regards the accusation), you have also consummated your marriage with her; and if you have told a lie, you are less rightful to have your money back.' ")
Allah's Messenger (ﷺ) separated (divorced) the wife from her husband who accused her for an illegal sexual intercourse, and made them take the oath of Lian .