What is the ruling on Mut'ah (temporary marriage), and what are the opinions of the jurists regarding it if the contract is concluded between the two parties with only a dowry, without witnesses, and without specifying a duration, when there is a necessity for it, and there is concern about harm and falling into sin?

"Mut'ah" marriage (temporary marriage) is invalid and forbidden by consensus, and a condition for the validity of marriage is the presence of witnesses. If the marriage is invalid, then it is not permissible to enjoy the woman, by agreement of the four imams. There is no necessity that permits a forbidden marriage; rather, the determination of necessity falls to the people of knowledge, not to personal desires.