The importance of establishing Prayer has been mentioned in the Holy Quran and Hadith, on several occasions:
Allah the Supreme states in the Holy Quran: “And keep the Prayer established, and pay the charity, and bow your heads with those who bow (in Prayer).”(Surah Baqarah)

On another occasion, it is stated: “Guard all your Prayers and the middle Prayer; and stand with reverence before Allah.” (Surah Baqarah)

On yet another occasion, it is stated: “And keep the Prayer established at the two ends of the day and in some parts of the night.” (Surah Hud)

The “two ends of the day” mean the morning and evening. The time before noon is classified as morning and the time after it is classified as evening. The Morning Prayer is the Dawn (Fajr) prayer, and the Prayers of the evening are the Afternoon (Zohr) and the Evening (Asr) Prayers. The Prayers for the night are the Sunset (Maghrib) and the Night (Isha) Prayers. (Tafseer Khazain ul Irfan)

The Holy Quran classifies Prayer as an act that is opposite to the habits of polytheists. It states, “Inclining towards Him – and fear Him, and keep the Prayer established, and never be of the polytheists.” (Surah Ruum)

In other words, not offering the Prayer is to be like the polytheists. This is further confirmed by the words of the Holy Prophet “The entity that lies between a bondman and disbelief, is the abandonment of Prayer.” (Saheeh Muslim)

The Holy Quran warns those who abandon Prayer, in the following words: “And after them came the unworthy successors who squandered Prayer and pursued their own desires, so they will soon encounter the forest of Gai in hell.” (Surah Maryam)

‘Gai’ is a well in the lowest part of hell, which accumulates the pus of its inhabitants. It is also mentioned that ‘Gai’ is the hottest and deepest part of hell. This is the well that Allah opens up whenever the heat of hell lessens, causing the fire of hell to rage again. This well is the destination of those who abandon Prayer and adulterers, drunkards, usurers, and those who hurt their parents.

The Holy Quran has mentioned a trait of the hypocrites, that they are lazy in offering Prayers, and that they deem it to be a burden. It, therefore, states: “Undoubtedly the hypocrites, in their fancy, seek to deceive Allah whereas He will extinguish them while making them oblivious; and when they stand up for Prayer, they do it unwillingly and for others to see, and they do not remember Allah except a little.”(Surah Nisaa)

The Holy Prophet has said the following about the hypocrites: “The most burdensome prayers for the hypocrites are the Night Prayer and the Dawn Prayer. If they were to know the blessings they have in store, they would have come to them, even slithering.” (Saheeh Bukhari and Saheeh Muslim)

The Holy Quran also explains that offering the Prayer is not at all a burden for those who believe in Allah and the Last Day. It says: “And seek help in patience and prayer; and truly it is hard except for those who prostrate before Me with sincerity – Who know that they have to meet their Lord and that it is to Him they are to return.” (Surah Baqarah)

We, therefore, know from the Holy Quran, and from the Hadith, that it is obligatory for all Muslims to offer Prayers 5 times daily. To be lazy in Prayer, and especially not to offer the Night and Dawn Prayers, are the traits of hypocrites. We also know that not offering Prayer is the way of the disbelievers – this is why the Sahabah (the Companions of the Holy Prophet) did not deem the abandonment of any deed as disbelief, except the abandonment of Prayer.
The importance of Prayer can be gauged from the fact that it has been emphasized right from childhood. The Holy Prophet has said:”Command your children to pray when they become seven years old, and beat them for it (Prayer) when they become ten years old; and arrange their beds (to sleep) separately.