About the garb and appearance of all the Imams (a.s.) suffice it is to say that they never appeared and dressed in a manner to earn for themselves special distinctions. In all their affairs, they lived a moderate life. The essential condition of moderation is to live among the common society, and to proceed along with them (as long as it doesn’t lead to sin).
To elaborate this matter, it is necessary to remind the following points:
Whenever the holy Prophet (s.a.w.a.) would sit together with a group of people, none could tell one from the other. He would not earmark a special place for himself. When a stranger would arrive, he couldn’t distinguish the Prophet among the crowd. From this practice, it becomes clear that his apperance and dress was like the common people.
We conclude from the Prophet’s sunnah that Hazrat Mahdi’s dress is in harmony with the clothing of the common people (as long as it is not forbidden, or disapproved, and is not inappropriate with Imam’s lofty position). Imam avoids clothing that may attract the attention of hundreds of thousands of people. During his Reappearance, he will dress like the people of that time except if that dress is inappropriate with Islamic principles. In such a case, his followers too would wear clothes like their Imam.
About his dress, it has come down in a tradition in Bihar-ul-Anwar 52: 11
“His dress is coarse and his food is very simple” .
From this noble tradition, we conclude that his dress is not soft and comfortable, but rather rough, thick and coarse. Besides, its colour, quality and design are not in a manner that gives special distinction over other peoples’ dress. The immaculate Imams (a.s.) have themselves recommended that:“Live in the society while not making yourself conspicuous” . In confirmation with this saying, it has come down in Shia Fiqh that it is unlawful and forbidden for a male to wear a female dress, or a female to wear a male dress; or for anyone to wear any distinctive clothes. The jurists have given a decree that it is unlawful to wear distinctive clothes. Distinctive clothes means a dress worn by someone, who makes himself conspicuous among the people such that they say,“Look at him, he is wearing such and such dress!” .
From this point, one can understand that Imam’s dress is an ordinary and common dress.
Those who were fortunate in visiting him, have seen him in ordinary and sober native dress. In the hajj journey, he has been seen in the dress of the Arabs. In Najaf, in the dress of the clerics and at other places in ordinary clothes, so that he has not attracted the people’s attention.
All these are probabilities acquired from general rules and principles. But its exact details specially at the time of his advent is only known to Allah.