Issue 500: One must perform two prostrations after bowing in every Rak'at of a recommended or obligatory prayer.

Issue 501: To perform prostrations, one must place their forehead, palms, knees and the tips of their big toes on the ground and it is obligatory to say a Remembrance when they prostrate. These two prostrations are accounted as an element (Rukn) of the prayer.

Issue 502: Any remembrance would suffice for prostrations, but it must not be shorter than three times "Subhanallah", or once "Subhana Rabbiyal aa'la wa bihamdih".

Issue 503: While saying the remembrance of the prostration, one's body must be still.

Issue 504: If one intentionally says the remembrance of the prostration before their body is still and their forehead reaches the ground, their prayer will be void, and if one does so due to forgetting, they must say the remembrance again when their body is still.

Issue 505: After the remembrance of the first prostration is completed, one must rise from prostration and sit still, before they perform the second prostration.

Issue 506: If a person intentionally raises their head from prostration before the remembrance is completely said, their prayer will be void.

Issue 507: If one intentionally lifts one of their seven limbs from the ground while pronouncing the remembrance of the prostration, their prayer will be void, but when they are not reciting the remembrance, if they raise any of these limbs except their forehead, and place them back on the ground, their prayers will not be void.

Issue 508: If one places their toes, or their insteps on the ground along with the tips of their big toes while prostrating, or if the tips of the big toes do not rest on the ground due to very long nails, their prayer will be void.

Issue 509: In prostration, one must place their forehead on the ground or on what grows from the earth which is neither clothing nor an edible staff, like leaves of the trees and wood.

Issue 510: To prostrate on minerals like gold, silver, agate and turquoise is not valid. But it does not matter to use mineral stones like marble and black stones.

Issue 511: To prostrate on the things which grow from the earth and serve as fodder for animals, like grass and hay is valid.

Issue 512: To prostrate on paper is valid, even though it is made out of cotton and the like.

Issue 513: The soil of the grave of Imam Al-Hossain (PBUH) is the best thing for prostration, and after that, there stand soil, stone and grass in order of priority.

Issue 514: If the clay disk (Muhr) sticks to the forehead in the first prostration, it should be removed from the forehead before performing the second prostration; otherwise the prayer will be void and must be redone.

Issue 515: The point where one places his/her forehead in prostration must not be more than four attached fingers higher or lower, compared to the point where they put their knees, and as an obligatory precaution, compared to the point where they place the tips of their toes.

Issue 516: Nothing must intervene between one's forehead and the thing on which they perform the prostration. So, if the clay disk is so dirty that one's forehead does not reach the clay, the prostration will be void, but if the color of the clay disk has changed, the prostration will not be void.

Issue 517: A person who is offering prayers, must place their big toes on the ground, and it will suffice to put the big toes on the ground in any position, but the recommended precaution is to put only the tips of the big toes on the ground, and if they put their other toes or insteps on the ground or if their big toes do not reach the ground due to very big nails, the prayer will be void.

Issue 518: The clay disk or whatever the prostrations are performed on, must be pure, but if one puts the clay disk on an impure carpet or if they place their forehead on the pure side of a clay disk whose other side is impure, their prostration will be valid.

Issue 519: Where it is necessary to dissimulate, that is, to hide one's thoughts and true beliefs because of their life being in danger, they can prostrate on carpets and the like, and it is not necessary to go to a different place for prostration.