Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) was asked about mut'ah marriage, and he said: Unlawful. If Umar bin al-Khattab (may Allah be pleased with him) caught anyone in it, he would stone him with stones.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14173