‘Ali ibn Abi Tālib (may Allah be pleased with him) reported that the Prophet (may Allah's peace and blessings be upon him) prohibited the fixed term marriage on the Day of Khaybar and eating the flesh of domestic donkeys.
The objective of marriage in Islam is to establish a continuous relationship based on affection and to build a family. Islam has prohibited some forms of marriages that contradict this objective. For this reason, the Prophet (may Allah's peace and blessings be upon him) prohibited Mut‘ah (fixed term) marriage at the time of the battle of Khaybar. This form of marriage, in which a man marries a women for a certain period of time, was made permissible at the beginning of Islam because there was a necessity for it. Similarly, the Prophet (may Allah's peace and blessings be upon him) prohibited consumption of domestic donkeys that are possessed and taken care of by other people, unlike the wild donkeys.