حَدَّثَنَا عَلِيٌّ، حَدَّثَنَا سُفْيَانُ، قَالَ عَمْرٌو عَنِ الْحَسَنِ بْنِ مُحَمَّدٍ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ، وَسَلَمَةَ بْنِ الأَكْوَعِ، قَالاَ كُنَّا فِي جَيْشٍ فَأَتَانَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ إِنَّهُ قَدْ أُذِنَ لَكُمْ أَنْ تَسْتَمْتِعُوا فَاسْتَمْتِعُوا ‏"‏‏.‏

Narrated Jabir bin `Abdullah and Salama bin Al-Akwa`: While we were in an army, Allah's Messenger (PBUH) came to us and said, "You have been allowed to do the Mut'a (marriage), so do it." Translation Not Available

Book Ref: Sahih Bukhari Book 67 Hadith 5117, 5118
Web Ref:  Sahih Bukhari Vol 7 Book 62 Hadith 52