In Islam, performing the prayer is the most important, mandatory act after the testimony of faith. The Prophet, sallallaahu ‘alaihi wa sallam, (may Allah exalt his mention ) said: “The head of the matter is Islam, its pillar is the prayer...”[At-Tirmithi]
It is the last thing, the Prophet, sallallaahu ‘alaihi wa sallam, recommended to his nation before he died, saying: “The prayer, the prayer and what your right hands possessed.” [Abu Daawood] An act of this weight and status is really worthy of getting all attention and care of Muslims. Because the prayer which Allah accepts and rewards plentifully is the prayer whose conditions, and basic elements are perfected.
But how could one carry out the prayer in the correct manner? One could attain that goal by learning the way the Prophet, sallallaahu ‘alaihi wa sallam, practised it. By knowing its prerequisites, essentials and Sunnah acts. Because botching the prayer is a harmful act that results in the forfeiture of the reward, either completely or partially, the Prophet, sallallaahu ‘alaihi wa sallam, warned us: “Truly, a man leaves, and none of his prayer has been recorded for him except a tenth of it, a ninth of it, eighth of it, seventh of it, sixth of it, fifth of it, fourth of it, third of it, a half of it.”[Abu Daawood]
Here is a detailed description of the prerequisites (Shuroot) and essentials (Arkaan) of the Prayer is presented.
There is a difference between the terms “prerequisite” and “essential”. The former is an object, quality, or condition that is required in order for something else to happen - and if it is missing, the thing is invalid and unfulfilled. For instance, Wudhoo’ (ablution) is a prerequisite for the prayer, as per the Prophetic narration: “The prayer of one without purification is void...” [Abu Daawood and At-Tirmithi] While “essential” is the property or characteristic of something that makes it what it is - and if it is missing the thing is null and void. For instance, the chapter of Al-Faatihah (the Opening of the Qur’an) is an essential for the prayer because the Prophet, sallallaahu ‘alaihi wa sallam, said: “Anyone who does not recite the Opening of the Book in one’s prayer is not credited with observing it.” [Al-Bukhari]
The scholars concur that a willful violation of any essential or prerequisite in prayer invalidates it. However, when an essential act is unintentionally omitted, two things are required: 1. performing the missing act and; 2. making Sujood as-Sahw (prostration of mistake) before Tasleem (concluding the prayer with salaam) if it is on account of an omission or due to both an omission and an addition; or after Tasleem if the cause is only an addition. However, if the mistake is one of involuntary addition - such as an extra bowing - it is atonable by Sujood as-Sahw.
It is obligatory on the one who wishes to perform the prayer to make sure that he/she satisfies the following conditions before he enters into it:
(1) Islam: One must be a Muslim in order for him/her to obtain the rewards of Islamic acts of worship.
(2) Intention (Niyyah): The Prophet, sallallaahu ‘alaihi wa sallam, said: “Verily all actions are only by intentions.” [Al-Bukhari and Muslim]
Scholars of all of the four schools of jurisprudence are unanimous that intention takes place in the heart and that it should not be uttered by the tongue. The Prophet, sallallaahu ‘alaihi wa sallam, never instructed us to audibly or inaudibly state intentions for any act of worship, and the Companions, may Allah be pleased with them, did not do this either. According to a few of the late scholars, one is only permitted to utter one’s intention in prayer if one is in a severe case of forgetfulness or always doubting what he wants to do - the term they coined to describe the state of such a person is Al-Mustankah.
(3) Sanity and maturity: One must be able to know and appreciate what he/she is doing. Sanity is mentioned in the narration in which the Prophet, sallallaahu ‘alaihi wa sallam, said: “The pen (which records one’s deeds) is raised from the account of a person in the following three situations: a sleeper until he awakes, a child until he matures (reaches age of puberty) and the insane until he regains sanity.” [Abu Daawood]
One must also have a clear mind at the time of making the prayer. Allah Says (what means): “O you who have believed, do not approach prayer while you are intoxicated until you know what you are saying…”[Qur’an 4: 43] In addition, the Prophet, sallallaahu ‘alaihi wa sallam, also said: “If one feels drowsy while performing the prayer, one should go to sleep until his slumber is over, because if one perform the prayer while drowsy one would not know whether he is asking for forgiveness or for a bad thing for himself.”[Al-Bukhari]
(4) Knowing the prayer’s proper time: Allah Says (what means): “…Indeed, the prayer has been decreed upon the believers a decree of specified times.” [Qur’an 4: 103] The Prophet, sallallaahu ‘alaihi wa sallam,, said: “Jibreel led me in prayer at the Ka’aba. He led me in the early afternoon prayer (Dhuhr) when the sun had passed the meridian to the extent of the throng of a sandal; he led me in the mid-afternoon prayer (‘Asr) when the shadow of a thing was as long as itself; he led me in the sundown prayer (Maghrib) when the one who fasts breaks the fast; he led me in the night prayer (‘Ishaa’) when the twilight (redness from the horizon at sunset) disappears; he led me in the dawn prayer (Fajr) when food and drink becomes forbidden for the faster. On the following day, he led me in the early afternoon prayer (Dhuhr) when the shadow of a thing was as long as itself; he led me in the mid-afternoon prayer (‘Asr) when the shadow of a thing was twice as long as itself; he led me in the sundown prayer (Maghrib) when the one who fasts breaks the fast; he led me in the night prayer (‘Ishaa’) when the first half of the night had passed; he led me in the dawn prayer (Fajr) when there was a fair amount of daylight. Then turning to me Jibreel said, ‘Muhammad, this is the time observed by the prophets before you and the difference in time for each prayer we made on both days is anywhere between the two times.’”[Abu Daawood]
(5) Purification: One must make sure that the following three things are clear from all kinds of impurity before he starts the prayer:
A. Purity of the body from major and minor impurities:
A minor impurity is one that may be removed by the performance of ablution (Wudhoo’). A state of minor impurity results after defecation or urination. A major impurity requires the performance of Ghusl or ritual bathing. A state of major impurity results after sexual intercourse or sexual discharge for both men and women.
If one is not in the necessary state of purification then one must attain it for Allah Says (what means): “O you who have believed, when you rise to [perform] the prayer, wash your faces and your forearms to the elbows and wipe over your heads and wash your feet to the ankles And if you are in a state of janaabah (major impurity), then purify yourselves…” [Qur’an 5: 6]
And the Prophet, sallallaahu ‘alaihi wa sallam, said: “When you stand for prayer, perfect your ablution,” [Al-Bukhari and Abu Daawood] and “the prayer is not accepted from anyone who nullifies one’s ablution until she/he regains another one nor is charity from stolen property.” [Al-Bukhari and Muslim]
The Prophet, sallallaahu ‘alaihi wa sallam, also said: “Allah does not accept any prayer that was not performed while in a state of purity, nor does he accept charity from what has been stolen from booty.” [Al-Bukhari & Muslim]
Post-natal bleeding and menstrual bleeding are also considered forms of major impurity. Both postnatal bleeding and menstrual bleeding waives the prayer from a woman. In those cases, after such conditions come to an end, women are required to make Ghusl before praying.   
B. Clothes: if the clothes are contaminated with impurities one should wash them for Allah Says (what means): “And your clothing purify.” [Qur’an 74: 4] and the Prophet, sallallaahu ‘alaihi wa sallam, said: “If menstrual blood is on one’s clothes she must wash it out and then perform prayer.” [Al-Bukhari]
C. Place: If the ground is filthy, one can pour water over the impurity: A Bedouin entered the Masjid (mosque) and urinated. The people grabbed him and the Prophet, sallallaahu ‘alaihi wa sallam, ordered his release, told them to pour a tumbler of water over the soiled area, and said: “You have been sent to make things easy and not make them difficult.” [Al-Bukhari]
It is prohibited to offer prayer in graveyards [Muslim], camel pens [Abu Daawood], churches and synagogues with images [Al-Bukhari], public baths/bathrooms and dunghills [Abu Daawood], the roof of the Ka’aba, slaughterhouses, and the middle of the road.
(6) Covering the private parts: Allah Says (what means): “O children of Aadam, take your adornment at every Masjid (mosque)…” [Qur’an 7: 31] The meaning of “adornment” here is the covering of the ‘Awrah. The meaning of “mosque” is “prayer.” Therefore, it means “Cover your ‘Awrah for every prayer.”
The ‘Awrah for a man, in general, is from his navel to his knees; however, inside prayer one should be dressed in a proper manner and the shoulders should not be left uncovered since it is greatly disliked. The ‘Awrah of a woman (for prayer purposes) is her entire body except her face and hands.
(7) Facing the Qiblah: Allah Says (what means): “Turn your face in the direction of Al-Masjid Al-Haraam (Sacred Mosque), and wherever you are turn your faces (in prayer) in that direction.” [Qur’an 2: 144] The Prophet, sallallaahu ‘alaihi wa sallam, said: “When you stand for prayer face the Qiblah, make takbeer, utter glorification and praise for Allah, recite the Mother of the Book (Al-Faatihah)...”[Al-Bukhari and Abu Daawood]
There are many ways to decide the Qiblah. And when one is ignorant of the right direction, one should inquire and strive to determine its exact or approximate direction, and in case neither of the two is possible one should follow his best judgment.

Article source: http://www.islamweb.net/emainpage/


Necessary conditions for the prayer
The essentials of prayer are:
(1) Saying the opening takbeer: It is done when one commences with prayer by saying “Allahu Akbar” (Allah is the greatest) while raising the hands to shoulder level with the palms facing forward. The Prophet, sallallaahu ‘alaihi wa sallam, (may Allah exalt his mention ) said: “The key to prayer is purification, its beginning is takbeer, and its end is tasleem.” [Abu Daawood and At-Tirmithi]
(2) Standing (Qiyaam) after the first takbeer: One must stand during the prayer, if one is able. Allah Commands (what means): “Maintain with care the [obligatory] prayers and [in particular] the middle prayer and stand before Allah, devoutly obedient.” [Qur’an 2: 238],  and the Prophet, sallallaahu ‘alaihi wa sallam, said: “When you stand for prayer face the Qiblah, make takbeer, utter glorification and praise Allah (Du’aa’ of Istiftaah), recite the Mother of the Book (Al-Faatihah).”[Al-Bukhari] And Allah Says (what means): “So when you recite the Qur’an, [first] seek refuge in Allah from Satan, the expelled [from His mercy].” [Qur’an 16: 98]
If one cannot stand, he may perform prayer sitting, lying on one’s side or whatever position he is capable of taking. The Prophet, sallallaahu ‘alaihi wa sallam, said to ‘Umraan Ibn Husayn, may Allah be pleased with him: “Pray standing; if you are not able to, pray sitting; if you are not able to, pray (while lying) on your side.” [Al-Bukhari] As for the voluntary prayer, one can do it sitting even if he can stand, but one who stands receives a greater reward than one who sits. ‘Abdullaah Ibn ‘Umar, may Allah be pleased with him, narrated that the Prophet, sallallaahu ‘alaihi wa sallam, said: “The prayer of one who sits is half of the prayer (of one who performs it standing).” [Al-Bukhari and Muslim]
(3) Reciting Al-Faatihah in every Rak’ah (unit) of the prayer. While standing one must properly recite the chapter of Al-Faatihah. The Prophet, sallallaahu ‘alaihi wa sallam, stated: “If anyone makes prayer and does not recite the chapter of Al-Faatihah, then his prayer is deficient and not complete...” [Muslim and Abu Daawood]
(4) Bowing: Allah Says (what means): “O you who have believed, bow and prostrate...” [Qur’an 22: 77] The manner of bowing is accomplished by bending over, putting one’s hands on one’s knees, and remaining in that position until one attains calmness.
(5) Resuming the initial standing position: In a famous narration, the Companion Abu Humayd, may Allah be pleased with him, described what the Prophet, sallallaahu ‘alaihi wa sallam, did after bowing, saying: “He would raise his head from his bowing, and then stand straight until all of his backbones returned to their places.” [Al-Bukhari and Muslim]
(6) Prostration: The Prophet, sallallaahu ‘alaihi wa sallam, explained the proper prostration by saying, “Then prostrate until you attain calmness in your prostration, then rise (and sit) until you attain calmness in your sitting, and then prostrate until you gain calmness in your prostration...” [Al-Bukhari]
(7-8) Rising in a sitting position and sitting between prostrations: Rising in a sitting position and taking a short rest in a sitting posture between the two prostrations are obligatory acts in prayer.
(9-10) The final sitting and recital of the testimonial (tashahhud): Ibn ‘Abbaas, may Allah be pleased with him, said: “The Messenger of Allah used to teach us the Tashahhud like he taught us the Qur’an. He would say: “Attahiyyatu lillaahi was-salawaatu wat-tayyibaatu. Assalaamu alayka ayyuhan-nabiyyu wa rahmatullaahi wa barakaatuhu. Assalaamu alaynaa wa alaa ibaadillaahis-saaliheen. Ashhadu al-laa ilaaha illallaaah wa ashhadu anna Muhammadan abduhoo wa rasooluh”
(Salutations, blessings, prayers and good deeds are for Allah. Peace be upon you, O Prophet, and the mercy of Allah and His blessings. Peace be upon us and the sincere slaves of Allah. I bear witness that there is no god except Allah. I bear witness that Muhammad is His slave and messenger).” [Muslim and Abu Daawood]
(11) Termination (tasleem): This is when one concludes the prayer by looking to the right and left, saying “Assalamu alaykum wa rahmatullaah” (peace and Allah’s mercy be upon you). ‘Amr Ibn Sa’d, may Allah have mercy upon him, related that his father, may Allah be pleased with him, said: “I saw the Prophet, sallallaahu ‘alaihi wa sallam, saying the salaam on his right side and on his left side until I could see the whiteness of his cheeks.” [Muslim and Ahmad]
The majority of scholars, excepting the Hanbalis, consider uttering salaam once as sufficient.
(12) Calmness (toma’neenah): All acts and positions of prayer should be executed with calmness. Calmness is achieved by sitting in the position until the bones are set and still.
The Companion Abu Humayd, may Allah be pleased with him, said: “I am well-informed about the prayer of the Messenger of Allah, sallallaahu ‘alaihi wa sallam, and I saw him stand for prayer raising both hands to the shoulders and uttered takbeer until every bone rested in its place properly with calmness; recited the chapter of Al-Faatihah and uttered takbeer raising both hands to the shoulders; then he bowed placing his palms on his knees keeping his back straight/parallel to the floor with calmness; then stood up straight with calmness saying “Sami’Allahu liman hamidah, rabbanaa wa lakal-hamd” while raising both hands to the shoulders; then while saying takbeer, he prostrated; then he sat up onto his left foot with the right foot propped up while saying takbeer; then prostrated again while saying takbeer; then momentarily sat up again (the sitting of rest) before standing for the second unit (Rak’ah) to repeat all of the above except the opening takbeer and Duaa’ of Istiftaah. In the second Rak’ah (at the point of the sitting rest), he sat more than momentarily to recite tashhahhud and prayer on the Prophet, sallallaahu ‘alaihi wa sallam. In the last rak’ah, he pushed his left foot forward and sat on his left hip and recited two additional supplications before concluding.” [Al-Bukhari and Abu Daawood]
(13) Sequence: Proper sequence is mandatory between the different acts of prayer. Hence the opening takbeer must come before reciting, the reciting must precede bowing, and bowing must happen before the prostration, and so on.
Conclusion
Undoubtedly, the fulfilment of all the necessary conditions for the prayer enhances its chances of receiving the recognition and reward of Allah. However, the satisfaction of the essentials and prerequisites of the prayer is not the only guarantee for success in this great act of worship. There are also other things a Muslim should learn such as the invalidators of prayer, its Sunnah acts, its recommended acts, etc.

Article source: http://www.islamweb.net/emainpage/