Temporary marriage is an established Shi’ite concept. Shi’ites justify temporary marriage, mutah, by their reading of Qur’an 4:24:
And all married women (are forbidden unto you) save those (captives) whom your right hands possess. It is a decree of Allah for you. Lawful unto you are all beyond those mentioned, so that ye seek them with your wealth in honest wedlock, not debauchery. And those of whom ye seek content (by marrying them), give unto them their portions as a duty. And there is no sin for you in what ye do by mutual agreement after the duty (hath been done). Lo! Allah is ever Knower, Wise.
They see in this marriage as something contracted by means of payment (“give them their portions”) for a specified time by mutual agreement.
However, it is also found among Sunnis. We have seen it in Egypt, and it has been reported as also rising among Saudis.
“IS Executes Women in Mosul For Refusing Temporary Marriage,” Basnews, January 25, 2015 (thanks to The Religion of Peace):
The Islamic State (IS) militants have executed seven women in Mosul for refusing temporary marriage, or ‘nikah’.
Kurdistan Democratic Party (KDP) official from Mosul Saed Mamuzini told BasNews that IS are demanding women accept nikah with insurgents. Nikah is a temporary marriage which permits the participants to have sex.
“Many women refuse to have sex with IS militants, in which cases they are arrested. The militants often kill them,” said Mamuzini.
“Today [Saturday] seven women from Mosul were killed at the IS base of Ghazlan,” he added.
Mamuzini claimed that these women had refused to enter in nikah with IS insurgents.
IS tell women that if they have sex with IS insurgents within the contract of nikah, it will be considered jihad for women.