If someone performs prayers with usurped clothing to protect his life, then in case he cannot perform prayers with other clothing by the end of the prescribed time, or he has to wear it out of necessity due to no fault of his own – for example, he did not usurp it himself – his prayers are valid.
Similarly, if he performs prayers in usurped clothing so that a thief does not steal it and he cannot perform prayers before the end of the prescribed time with other clothing, or he keeps it with the intention of returning it to its owner as soon as possible, his prayers are valid.
Ruling 807.* If a person purchases clothing with money on which the one-fifth tax (khums) has not been paid, and the purchase is a non-specified undertaking (al‑kullī fī al‑dhimmah),[3] as most purchases are, the clothing will be lawful (ḥalāl) for him. However, because he used money on which khums had not been paid, and he delayed paying the khums that was due on it, he will have sinned and must pay khums on the money he gave to the seller.
However, if a person purchases clothing with the actual money on which khums has not been paid,[4] then performing prayers with that clothing without the authorisation of a fully qualified jurist (al‑ḥākim al‑sharʿī) is ruled to be the same as performing prayers with usurped clothing.