821. The clothing a person utilizes to conceal his private parts whilst praying must be mubÁÎ (not usurped). If a person who knows that the utilization of usurped clothing is forbidden, or due to his negligence did not learn the ruling that wearing usurped clothing is prohibited, knowingly conceals his private parts by means of usurped clothing, his prayer is invalid.
However, in the following cases, the utilization of usurped clothing does not cause the invalidation of prayer, though the precaution is that it should be avoided:
a. When the article of clothing is insufficient to conceal the private parts.
b. When the article of clothing is sufficient for concealing the private parts, but is not being worn during prayer, like a large handkerchief or a loincloth that is in one’s pocket, given that it does not move along with the movement of the one who is praying. However, if it moves along with his movements, then praying in it would be problematic.
c. When a usurped article of clothing is utilized for other than concealing the private parts.

822. If a person knows that the utilization of usurped clothing is forbidden, but does not know that using it to conceal the private parts during prayer invalidates the prayer, and he intentionally utilizes it whilst praying, his prayer is invalid.

823. If a person utilizes usurped clothing to conceal his private parts during prayer, but he is unaware that it is usurped, his prayer is valid. Similarly, the prayer of a person who forgetfully utilizes usurped clothing and he is not the usurper, is valid.
However, if one who usurped the clothing himself, forgets that he usurped it, and utilizes it to conceal his private parts, his prayer is invalid if he has not repented for usurping it. If he has repented, to claim that his prayer is invalid is problematic.

Tayammum must be performed in lieu of ghusl or wuÃÙ in the following seven circumstances:

824. If a person does not know or forgets that his clothing is usurped, and realizes it whilst praying, he must remove the usurped clothing if his private parts are concealed by means of another article of clothing, and he is immediately able to remove the usurped clothing or he is able to do so without breaking the muwÁlÁt sequence of the prayer.
One must break his prayer and pray with clothes that are not usurped as long as there is sufficient time for at least one rak‘ah if:
a. There is nothing else concealing his private parts.
b. Or, he is unable to immediately remove the usurped clothing.
c. Or, removing the clothing would break the sequence of the prayer.
However, if the time left is insufficient for even one rak‘ah, he must take off the article of clothing while praying, and observe the rulings of those who pray unclothed as discussed in article 803.

First: when it is not possible to procure enough water for performing wuÃÙ or ghusl.

654. If the person is situated in a populated area, he should search for water for wuÃÙ or ghusl to an extent that he loses hope in finding water.
If he is situated in a desert, on uneven land, he should search for water for a distance covered by an arrow released from a normal bow (the kind used during the olden days). If he is on even land, he should search for twice this distance.
Obligatory precaution dictates that he search for water in the entire circular area having the aforementioned radii, centered at his location.

655. If some of the land around him is flat, and some of it uneven, he should search for the distance covered by an arrow in the uneven areas, and twice this distance in the flat areas, in the manner described in the previous article.

656. A person does not have to search for water in the directions that he is certain do not contain water, or has a proof authorized by the sharia, to that effect.

657. If a person whose time for prayer is not constrained, and is afforded enough time to procure water, attains certainty that water is available in an area which is further than the distance he is obligated to search, he should go to that area to procure water as long as it does not entail hardship or harm. The same will apply if a proof authorized by the sharia is established to that effect.
However, if he merely speculates that water may be available in an area, he does not have to go to that area even though it may be highly probable, unless he attains satisfaction. It is however more precautionary that he do so.

658. It is not necessary for a person himself to go searching for water; rather, he may send someone whose word satisfies him. In fact, the same will apply if the person is trustworthy and one does not have a reasonable doubt contrary to his statement, even though his statements may not evoke satisfaction. In both cases, if one person goes searching, it will suffice in lieu of the rest, even if they be many.

825. If a person prays with usurped clothing to save his life, or for example prays with usurped clothing to avoid its theft, his prayer is valid even though it may cover his private parts.

659. If a person speculates that he may have some water within his belongings, in his house, or within the group he is travelling with, he should search to an extent that he attains certainty or satisfaction that water is not available, or to an extent that he loses hope in finding water.

660. If a person searches for water before the time of prayer, and fails to find any, and he remains in that area until the time of prayer, obligatory precaution dictates that if he speculates that water may have been located within the area, he should not suffice himself with the search that was conducted earlier, unless it was conducted close to the time of prayer, such that it would allow him to offer prayer at its prime time.

826. If a person purchases clothing with the very money on which khums has not been paid, then the ruling of praying with such clothing is that of praying with usurped clothing.

661. If he searches for water after the time of prayer sets in, and fails to find any, and he remains in that area until the time for the subsequent prayer, obligatory precaution dictates that if he speculates that water may have been located within the area, he should conduct another search for water.

662. It is not necessary to search for water in the following cases:
a. when the time for prayer is constrained
b. when one fears from thieves or wild animals for his life, or belongings which are significant in accordance to his status
c. when searching for water is so difficult, that undertaking the search entails hardship

663. If a person does not go searching for water until the time left for prayer becomes constrained, he will have committed a sin. However, his prayer offered with tayammum will be valid, even if he later comes to know that had he gone searching for water, he may have found it. The recommended precaution is that he also offers the qaÃÁ of the prayer.

664. If a person who has certainty that he cannot find any water, does not go searching for water, and offers his prayer with tayammum, only to realize later on that had he gone searching for water, he may have found some, he should offer his prayer again with wuÃÙ if the time for that prayer has not elapsed.

665. If a person does not find water after conducting a search for it, and offers his prayer with tayammum, only to realize later on that water was in fact available in the area that he searched, he should offer his prayer with wuÃÙ if the time for it has not elapsed. If it has, his prayer will be valid.