Sahih Bukhari Volume 7, Book 67, Hadith 5121

وَقَالَ ابْنُ أَبِي ذِئْبٍ حَدَّثَنِي إِيَاسُ بْنُ سَلَمَةَ بْنِ الأَكْوَعِ، عَنْ أَبِيهِ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏"‏ أَيُّمَا رَجُلٍ وَامْرَأَةٍ تَوَافَقَا فَعِشْرَةُ مَا بَيْنَهُمَا ثَلاَثُ لَيَالٍ فَإِنْ أَحَبَّا أَنْ يَتَزَايَدَا أَوْ يَتَتَارَكَا تَتَارَكَا ‏"‏‏.‏ فَمَا أَدْرِي أَشَىْءٌ كَانَ لَنَا خَاصَّةً أَمْ لِلنَّاسِ عَامَّةً‏.‏ قَالَ أَبُو عَبْدِ اللَّهِ وَبَيَّنَهُ عَلِيٌّ عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ مَنْسُوخٌ‏

Salama bin Al-Akwa' said: Allah's Apostle's said, "If a man and a woman agree (to marry temporarily), their marriage should last for three nights, and if they like to continue, they can do so; and if they want to separate, they can do so." I do not know whether that was only for us or for all the people in general. Abu Abdullah (Al-Bukhari) said: 'Ali made it clear that the Prophet said, "The Mut'a marriage has been cancelled (made unlawful)."