Salim bin Abdullah related that a man asked Abdullah bin Umar (may Allah be pleased with them both) about mut'ah marriage, and he said: "It is unlawful." The man said: But so-and-so says such-and-such about it! He said: "By Allah, it is well known that the Messenger of Allah (peace and blessings be upon him) made it unlawful on the day of Khaybar, and we were not fornicators."
The Shaykh said: Then the Messenger of Allah (peace and blessings be upon him) permitted mut'ah marriage at the time of the conquest of Makkah, and then made it unlawful until the Day of Resurrection.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14148