Arabic for "Night of Power," the most important night of the
holiest month of the year for
Muslims. Even so, nobody (except for God) knows what night it actually falls on.
The word Qadr is frequently translated as "The Power," though it's difficult to translate, it means a combination of Power, Fate, Grandeur, Preciousness, or Decree.
This night marks the night, Muslims believe, when the Qur'an was first revealed by the angel Gabriel to the Prophet Muhammad(pbuh).
Muslims everywhere know that this night is said to be equal to one thousand months and on this night the prayers of the sincere Muslim are certain to be answered. Pious Muslims spend most of this night praying and reading Qur'an. If you do good deeds during it, then their value is going to be multiplied tremendously on Judgment Day. Muhammad(pbuh) and his companions used to sleep at least one-third of the night, so it's reccomended to do the same.
Well, if it's so important, then when is it? We don't know. Some reports by the sahaba(companions or disciples) say that it is on the 27th of Ramadan, but more point it out to be during any of the odd-numbered nights during the last third of Ramadan. So therefore it can either be the 19th, 21st, 23rd, 25th, 27th or 29th night of Ramadan.
It's been said that the reason it's not specificaly defined is because God doesn't want us to pray on this one night and ignore Him the rest of the time. So instead people pray on ALL of these nights. Standing in prayer on this special night is like doing a lifetime of good deeds.
In Muslim countries, the 27th of Ramadan is a holiday to enable people to rest during the day after all night of worship. Schools are closed from the 27th of Ramadan through the 2nd of the next month of Shawwal (5 to 6 days total) to combine Laylat al-Qadr and 'Eid al-Fitr observances.
The Qur'an says thus in Chapter 97, Al-Qadr:
In the name of God, the Compassionate, the Merciful
Indeed We sent it (the Holy Qur'an) down on the Night of Power. What will convey to you what the Night of Power is like! Better is the Night of Power than a thousand months in that Night the angels and the Spirit descend
by the permission of their Lord for every affair. Peace it is, till the break of dawn.
Muhammad(pbuh) once said "He who spends the Night of Qadr in prayers, in full faith, shall have all his previous sins and guilt forgiven". (Hadith narrated by Al-Bukhari and Muslim)
Ayesha, his wife, said : "I asked the Prophet what to say during that night, on the assumption that I knew it was the night. He told me to say : 'God, you are the One who forgives, and you love to forgive, so forgive me.'"