Is it permissible to research the time of Imaam Mehdi's appearance?

Answer

Researching the time of Imaam Mehdi's appearance is futile. It is a waste of time. He will appear whenever he has to appear. Whatever the result of such research is, will be conjecture – personal opinion devoid of certitude. Furthermore, there is no benefit in it. If there was any benefit for mankind in knowing the exact time of Imaam Mehdi's appearance, Allah Ta'ala would have included it in the Shariah, and handed it to us on a platter in the same way as all the other Ahkaam have been presented to us on a platter.

Whatever the Shariah has kept majhool (ambiguous and unknown) should be left in that department. If someone should waste time researching something which in terms of the Shariah is superfluous, it will be in the category of laghw (futility). The Shariah commands abstention from futility. Whilst futility in its inceptional stage is a permissibility on which the Shariah frowns, it ultimately leads to sin.