The Invalidating Causes of Salat (Mubtilat)
The following causes render salat invalid:
1. Speech. Its minimum is anything composed of two letters, even if they are meaningless and of a single letter if it makes sense (such as the word قِ which is a verb in the imperative case of the root waqa).
The salat will not become batil by uttering a single letter which has no meaning and by an involuntary sound comprising many letters.
The Hanafis and the Hanbalis do not differentiate between intentional speech and anything spoken by mistake in respect of its being a cause that invalidates salat.
The Imamis, Shafi'is and Malikis observe: Salat is not invalidated by anything spoken by mistake provided it is short and does not vitiate the form of the salat.
The Imamis and the Malikis are of the opinion that salat is not invalidated by clearing the throat, irrespective of whether it is done due to necessity or not. The other schools consider it a cause that invalidates salat if done needlessly but not otherwise, such as for clearing one's voice for better phonation or for signalling the imam to correct himself.
The schools concur that it is valid to supplicate during salat, seeking blessing and forgiveness from Allah, subhanahu, except that the Hanafis and the Hanbalis restrict this supplication to what has been mentioned in the Qur'an and the Sunnah, or that which is sought only from God, such as rizq (provision) and barakah.
To recite tasbih (subhan Allah) to indicate that one is performing salat, or to guide the imam, or to correct his mistake, is not considered as a speech that invalidates salat.
The four Sunni schools state: Included in speech that invalidates salat is the returning of salam. Hence if someone says salam to a person who is praying and he returns the salam verbally, the salat becomes invalid. However, there is no harm if the salam is returned by a gesture.
The Imamis observe: It is wajib for the musalli to return a salutation which contains the word 'salam' with a similar salutation, though not any other salutation such as 'good morning', etc. They also specify that the form of the salutation being returned should be exactly like the initial salutation without any difference. Hence the reply of 'salam 'alaykum' will be the same without alif and lam, and the reply of 'al-salam 'alaykum' will be with the alif and lam.
2. Every action which destroys the form of the salat invalidates it. The schools concur that the form is destroyed by any act which gives an onlooker the impression that the person performing that act is not praying.
3. There is a consensus regarding eating and drinking though they differ regarding the quantity that invalidates salat.
The Imamis observe: Eating and drinking invalidate salat if they distort the form of salat or violate any of its conditions, such as continuity, etc.
The Hanafis observe: Every form of eating and drinking invalidates salat irrespective of the quanity consumed, even if it is one sesame seed or a drop of water and regardless of whether it is done intentionally or otherwise.
The Shafi'is state: Any food or drink which reaches the stomach of a musalli, irrespective of its being a small or a large quantity, invalidates salat if the musalli does so intentionally and with the knowledge of its being haram. But if done out of ignorance or forgetfulness, a small quantity will not invalidate salat, though a large quantity will.
According to the Hanbalis, a large quantity will invalidate salat, whether consumed intentionally or by mistake, and a small quantity only if consumed intentionally, not otherwise.
4. The occurrence of any minor or major hadath, which causes the wudu' or the ghusl to break, will also invalidate salat in the opinion of all the schools except the Hanafis, who observe: It will invalidate salat if it occurs before the last qu’ud (sitting) by a duration equal to tashahhud, and if it occurs after it and before taslim, the salat will not become invalid.
5. The schools concur that laughter invalidates salat, though the Hanafis apply to it the same rule that they apply to hadath, as mentioned above.
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Considering the importance of the causes that invalidate salat and their number and diversity, and considering that each school has its own opinion which at times concurs or differs with the opinions of other schools, it would be appropriate to give a summary of these causes in accordance with the opinion of.each school separately.
The Shafi'is observe: The causes invalidating salat are: hadath, which necessitates the performance of wudu’ or ghusl; speech; crying; groaning, in certain situations; inordinate movement(S), a doubt concerning niyyah; indecision concerning discontinuing the salat while continuing to perform it; shifting one's niyyah from one salat to another, except where it is an obligatory salat, for it is valid to change one's niyyah to that of a supererogatory salat in order to perform the obligatory salat with jama’ah; exposure of the 'awrah when one is capable of covering it; nakedness, as soon as a covering becomes available; the presence of najasah to an inexcusable extent, when one does not speedily remove it from himself; the repetition of takbirat al-ihram; intentional omission of a rukn; praying in jama’ah behind an imam who is not fit for imamah due to his kufr, etc; performing an additional rukn intentionally; the reaching of any food or drink to the stomach; turning away with the chest from the qiblah; and wrongly performing a rukn involving movement before other acts.
The Malikis say: Salat is invalidated by: omitting a rukn, intentionally or by mistake, if the musalli, thinking that his salat is correct, does not remember having omitted it until after taslim and the passage of an inordinate duration; intentionally performing an additional rukn, such as ruku’ or sujud; performing tashahhud out of place while sitting; laughter, both intentional and otherwise; eating and drinking intentionally; speaking intentionally and not for correcting the imam; vomiting, if intentional; puffing intentionally with the mouth; occurrence of anything that causes wudu’ to break; exposure of the 'awrah or any part of it; najasah falling on the musalli; inordinate movement; performing four additional rak'ahs in a four-rak’ah salat knowingly or by mistake; doing sujud before taslim; inadvertent omission of three masnun acts from among the sunan of salat and then failing to perform sujud al-sahw.
The Hanbalis state: The causes that invalidate salat are: any inordinate movement; the presence of najasah to an inexcusable extent; turning one's back to the qiblah; incidence of any hadath breaking the wudu'; intentional exposure of the 'awrah; reclining heavily on a support without any excuse; returning to perform the first tashahhud after starting the qira’ah, provided the musalli is aware and conscious of it; performing an additional rukn intentionally; intentionally changing the sequence of the arkan; mispronunciation that results in a change of meaning despite being capable of proper pronunciation; intending to disrupt the salat or indecision regarding it; a doubt regarding takbirat al-ihram; laughter, speech, both intentional or otherwise; saying taslim intentionally before the imam; eating and drinking, even if due to forgetfulness or ignorance; needlessly clearing the throat; any puffing that may be construed as phonation of two letters; and weeping if not out of the fear of God.
According to the Hanafis, the causes that invalidate salat are: speech, whether intentional, by mistake, or due to ignorance; any supplication (du'a') not out of the Qur'an or Sunnah; any inordinate movement; turning the chest away from the qiblah; eating and drinking; clearing the throat without reason; saying "uff" (i.e.'fie; or 'ugh'; an expression of anger or displeasure); groaning; saying "Ah!" (ta'awwuh); weeping loudly; saying "al-hamdulillah " on sneezing; saying "Inna lillah..." on hearing some bad news and "al-hamdulillah " on hearing some pleasing news; saying "subhan Allah" or "la ililha illallah" as an expression of surprise; availability of water for one praying with tayammum; the rising of the sun for one offering the morning prayer or its crossing the meridian for one performing salat al-‘id; the falling off of a bandage from one who attains recovery; wilful occurrence of hadath, but if the hadath is involuntary it will not invalidate the salat, though one will have to perform wudu’ again and recommence the salat from where he had left it.1
The Imamis observe: The causes that render salat invalid are: ostentation (riya'); uncertainty in niyyah; performing any act of salat while having made up one's mind to discontinue it; changing one's intent from a preceding salat to a subsequent salat, such as from zuhr to ‘asr. However, the transition from ‘asr to zuhr prayer is permissible; hence if a person makes the niyyah of performing 'asr prayer with the idea that he has performed the zuhr prayer and remembers during it that he has not performed the prayer, it is valid for him to shift his niyyah to offering the zuhr prayer. Similarly, it is permissible to shift from the niyyah of jama’ah to niyyah of performing it individually; but the opposite is not valid. However, it is valid for a person performing an obligatory salat individually to change his niyyah to that of a supererogatory salat in order to perform the obligatory salat with jama’ah. Salat is also invalidated by an additional takbirat al-ihram. Hence if one says takbirah for a salat and then repeats it, the salat becomes invalid and a third takbirah will be necessary. Again if he says takbirah for the fourth time, the salat will become invalid and a fifth takbirah will be neressary; thus every even takbirah results in the salat becoming batil due to the addition of a rukn, and becomes valid again by every odd takbirah.
Among the causes that invalidate salat is the incidence of najasah to an extent not excusable, when the musalli is unable to remove it without any inordinate movement that may vitiate the form of the salat. The availability of water during salat for a person praying with tayammum invalidates both the tayammum and salat, provided it becomes available before performing the ruku’ of the first rak’ah; if later, he will complete the salat which will be valid. Salat will also be invalidated by: the absence of certain conditions, such as the covering and the lawfulness of a particular location; the occurrence of a hadath; intentional deviation with the whole body from the qiblah either to the right or the left or any other direction in between; speaking voluntarily and weeping on account of one's worldly woes; laughter; any act that destroys the form of salat; eating and drinking; the intentional addition or omission of a part; and the omission, intentional or otherwise, of a rukn from among the five arkan. The five arkan are: niyyah, takbirat al-ihram, qiyam, ruku’ and the two sajdahs of every rak'ah.
The schools concur that someone's passing from in front of the musalli does not invalidate the salat, but they differ regarding its impermissibility.
The Imamis state: It is neither impermissible for a person to pass from in front of the musalli, nor for the latter (to pray in such a place). But it is mustahabb for the musalli to place before him an 'obstruction' if there is no barrier before him to prevent passers. The 'obstruction' can be a stick, a rope, a pile of earth, etc. which the musalli may place before him as a mark of veneration for salat, which signifies detachment from the creation and attention towards the Creator.
The Malikis, Hanafis and Hanbalis observe: It is haram to cross over in front of a musalli in any circumstance, irrespective of whether he has placed an obstruction or not. Rather, the Hanafis and the Malikis add: It is haram for the musalli to create interference for passers-by if he can keep out of their way.
According to the Shafi'is, it is haram to cross over in front of the musalli if he has not placed an obstruction, and if he has done so, it is neither haram nor makruh.
1. This is a summary from ‘al-Fiqh ‘ala’ al-madhahib al-‘arba’ah.