The 2nd Pillar of Islam
For a Muslim, after the declaration of faith the most important thing is the prayer. Allah (سبحانه و تعالى) says in the Quran:
“Verily, in the creation of the heavens and the earth, and in the alternation of night and day, there are indeed signs for men of understanding. Those who remember Allah (always, and in prayers) standing, sitting, and lying down on their sides, and think deeply about the creation of the heavens and the earth, (saying): Our Lord! You have not created (all) this without purpose, glory to You! (Exalted are You above all that they associate with You as partners). Give us salvation from the torment of the Fire” [Quran: Surah 'ali ‘Imraan 3: Ayahs 190-191]
One of the greatest reasons for which Allah (سبحانه و تعالى) has created mankind – which is also one of the greatest tests – is the command to affirm His Oneness (Tawheed) and to worship Him alone with no partner or associate. Allah (سبحانه و تعالى) has stated this reason for the creation of mankind, as He says:
“And I (Allah) created not the jinn and mankind except that they should worship Me (Alone)” [Quran: Surah al-Dhaariyaat 51: Ayah 56].
From the Sunnah, teachings of Prophet Muhammad (صلى الله عليه و سلم), we know:
Once a man asked the Prophet (صلى الله عليه و سلم) about the most virtuous deed. The Prophet (صلى الله عليه و سلم) stated that the most virtuous deed is the prayer. The man asked again and again. The first three times, the Prophet (صلى الله عليه و سلم) again answered, "The prayer," then on the fourth occasion he stated, "Jihad in the way of Allah." [This is form a hadith recorded by Ahmad and ibn Hibban. According to al-Albani, the hadith is hasan. Muhammad Nasir al-Din al-Albani, Sahih al-Targheeb wa al-Tarheeb (Beirut: al-Maktab al-Islami, 1982), vol. 1, p. 150]
- "The first matter that the slave will be brought to account for on the Day of Judgment is the prayer. If it is sound, then the rest of his deeds will be sound. And if it is bad, then the rest of his deeds will be bad." [Recorded by al-Tabarani. According to al-Albani, it is sahih. Al-Albani, Sahih al-Jami, vol.1, p. 503.
- "Allah has obligated five prayers. Whoever excellently performs their ablutions, prays them in their proper times, completes their bows, prostrations and khushu` [Khushu` in the prayer is where the person’s heart is attuned to the prayer. This feeling in the heart is then reflected on the body. The person remains still and calm. His gaze is also lowered. Even his voice is affected by this feeling in the heart], has a promise from Allah that He will forgive him. And whoever does not do that has no promise from Allah. He may either forgive him or punish him." [Recorded by Malik, Ahmad, Abu Dawud, al-Nasa’I and others. According to al-Albani, it is sahih. Al-Albani, Sahih al-Jami, vol. 1, p. 616.] ]
- The Prophet (صلى الله عليه و سلم) said "If a person had a stream outside his door and he bathed in it five times a day, do you think he would have any filth left on him?" The people said, "No filth would remain on him whatsoever." The Prophet (صلى الله عليه و سلم) then said, "That is like the five daily prayers: Allah wipes away the sins by them." (Recorded by al-Bukhari and Muslim.)
- In another hadith, the Prophet (صلى الله عليه و سلم) said, "The five daily prayers and the Friday Prayer until the Friday prayer are expiation for what is between them." [Muslim]
As for one who abandons the prayer deliberately and intentionally, without cause or justification, then he has disbelieved and left the fold of Islam, the evidence for this is:
Narrated from Jaabir ibn ‘Abd-Allah that the Prophet (صلى الله عليه و سلم) said: “Between a man and shirk and kufr there stands his neglect of the prayer.” [Narrated by Muslim in Kitaab al-Eemaan]
Likewise: "What lies between a man and disbelief is the abandonment of prayer." [Muslim, Aboo Dawood, Nasaa'ee]
Islam is a religion of mercy and allows one to repent and return to Islam. Allah (سبحانه و تعالى) says in the Quran:
“But if they repent [by rejecting Shirk (polytheism) and accept Islamic Monotheism], perform As-Salaat (Iqaamat-as-Salaat) and give Zakaat, then they are your brethren in religion.” [Quran: Surah al-Tawbah 9: Ayah 11]
This Ayah is also a proof that the difference between disbelief and Islam is the rejection of Shirk (associating anothers with Allah (سبحانه و تعالى)), and making the worship purely for Allah (سبحانه و تعالى), and performing the Salaah, prayer, and giving the Zakah, poor due, charity.