If someone’s fractured bone is set with an impure substance, he is not required to remove it when removal would cause him harm; and anything that separates from his body—whether a limb or a tooth—is pure.

Prayer is not valid in a cemetery, a refuse dump, a bathhouse, a camel corral, or on usurped land, nor on the roofs of such places; it is, however, valid if one merely faces them while praying.

An obligatory prayer is not valid inside the Kaʿbah or on its roof, whereas a voluntary prayer is permissible there provided the worshiper faces a clearly visible object within it.

Among the conditions is facing the qiblah. Without doing so the prayer is invalid, except for one who is unable or for a traveler performing a voluntary prayer while mounted. The mounted worshiper must open the prayer facing the qiblah, and a walking traveler must open, bow, and prostrate facing it. Whoever is close to the Kaʿbah must face it precisely, while one who is far away need only face its general direction. If a trustworthy person gives him certain information about it, or he finds a Muslim mihrab, he should rely on that.

While travelling he may determine the qiblah by the Pole Star, and he may also infer it from the sun, the moon, and their positions.

If two qualified scholars exercise ijtihad and reach different conclusions about the direction, neither need follow the other. A layperson follows whichever of them he considers more reliable. Whoever prays without either ijtihad or taqlid must repeat the prayer once he can find someone to emulate. A person acquainted with the evidences for determining the qiblah must make a fresh ijtihad for every prayer; he prays according to the subsequent determination and does not repeat what he offered in light of the first.

Another condition is intention: one must intend the specific prayer being performed. In an obligatory prayer it is unnecessary to specify in one’s intention whether it is on time or a make-up, and likewise, in a voluntary or repeated prayer1, to articulate that detail. He should also intend along with