Answer: Marriage is a union between man and woman. This union sometimes is permanent, without any limitation and sometimes is temporary with a time period being specified. Both of these are legal marriages; equal and the same and the only difference is for its duration: while one is permanent, the other is for a fixed period.
The following conditions are valid both in permanent or temporary marriages:
1) Man and woman should not have any legal obstacles in their marriage such as consanguineous or causative or any other legal obstacles, otherwise the marriage is void.
2) The dowry which is agreed by both sides should be mention in marriage contract.
3) The fixed period of marriage should be determined.
4) The marriage contract is legalized.
5) The child born in temporary marriage is legitimate and is just like a child born in permanent marriage and is entitled to have the identity card specifying the name of the father, and there is no difference between permanent and temporary marriage.
6) The child's expense is upon the father and the children inherit from both the parents.
7) When the period of marriage ends, the woman should keep the prescribed legal detachment period and if during the legal detachment it is found that she is pregnant, she should avoid any marriage until the baby is delivered.
Also, other rules of permanent marriage should be considered at the time of temporary marriage. The only difference is that the temporary marriage is for addressing the necessities.
The charges and expenses of the woman are not borne by man and if the woman at the time of marriage does not set out the condition of inheritance, she does not inherit from her husband. It is clear that these two differences do not have any impact on the marriage.
All of us believe that the Islamic rules are the final and eternal religious laws which answer all needs. Now consider a young man who is forced to live in another country for his studies for a long period of time and because of the limitation and lack of facilities cannot have a permanent marriage. He, therefore, has three choices:
A: He stays bachelor during the whole period.
B: He succumbs to corruption and fornication.
C: According to the above mentioned conditions, he marries a woman that legally permits marriage for a certain specified period of time.
In the first case, we frequently are confronted with failure, although a few are able to forego any sexual relationships and are patient and have forbearance; but this is not the case with all.
The condition of those who choose the second way is misery and corruption, which is also illegal in Islam. The thought of prescription of this method as a justification because of necessity is a kind of obliquity and malice.
Therefore, just the third way remains which Islam permits.
The point that is important to consider, is the permissibility of the temporary marriage is with specified qualifications. It does not mean that it is permitted at all times and unwarranted situations. Some people do perform temporary marriage for revelry. Some anecdotes from our holy leaders forbade the people from plethora in these matters.