Section on what invalidates the prayer

Everything that nullifies ritual purification likewise nullifies the prayer. It is also rendered invalid by deliberately exposing one’s private parts—except when they are uncovered by, say, a gust of wind and he covers them immediately, or even if he does not, provided the amount shown is not considered grossly immodest. The prayer is broken by turning one’s back to the qiblah where facing it is obligatory; by impurity touching him if he does not remove it at once; by excessive movement 1 that people customarily regard as much and that is unrelated to the prayer and undertaken without necessity; by leaning heavily on something without an excuse; by knowingly and deliberately returning to the first tashahhud after standing and beginning the Qurʾān recitation; by intentionally adding an extra physical pillar; by knowingly putting some pillars before others 2; by deliberately pronouncing the final salām before completing the prayer; by intentionally altering the meaning while reciting 3; by praying naked when some covering is available, even though it be at a distance; by revoking the intention (niyyah); by wavering about revoking it; by deciding to revoke it; by doubting whether one ever formed the intention and then performing any act while that doubt remains; by supplicating for mere worldly pleasures; by directing the second-person pronoun kāf to anyone other than Allah or His Messenger—according to Ahmad; by laughing aloud; by speaking, even unintentionally; by the follower stepping ahead of his imam—and both 4 thereby invalidate the imam’s prayer as well; by the follower giving the salām intentionally before the imam, or doing so inadvertently and failing to repeat it after him; and by eating or drinking 5 more than the small amount customarily overlooked, whether he does so knowingly, forgetfully, or out of ignorance. The prayer is not invalidated, however, if he swallows whatever is between his teeth provided he does not chew it.