Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) "forbade mut'ah (temporary marriage). It was only for one who could not find (the means of) marriage, but when marriage, divorce, the waiting period ('iddah) and inheritance between husband and wife came, it abrogated the mut'ah marriage."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14181
Bassam al-Sayrafi asked Ja'far bin Muhammad (may Allah have mercy on him) about mut'ah marriage and described it, and he said: "That is fornication (zina)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14182