Allah the Almighty, said:" Verily! We have sent
it (this Qur'an) down in the night of Al-Qadr (Decree). And what will you know what is
the night of Al-Qadr is?. The night of Al-Qadr is better than a thousands months (I.e.
worshipping Him a thousand moths, i.e. 83 years and 4 months). Therein descend the
angels and Rub [Jabreal] by Allah's permission with all Decrees. Peace! (All the night
there is peace and Goodness from Allah to His believing slaves) till the appearance of
dawn." (30:97). Also Allah said: "We sent it (this Qur'an) down
on a blessed night [night of Qadr]. Verily, We are ever warning. Therein (that night)
is decreed every matter of ordianment." (25:44:3-4).
The night of Qadr is a blessed night where the Qur'an was revealed, and decreed every matter, i.e the matter of death, birth, provisions, calmities, etc. for the whole (coming) year as decreed by Allah.
Narrated Aish, may Allah be pleased with her, Allah's Messenger, peace be upon him, said, "Search for the night of Qadr in odd nights of the last ten days of Ramadan." (Bukhari)
Aish, may Allah be pleased with her, related: I said, "O Messenger of Allah! What supplication should I recite if find the night of Qadr? he, peace be upon him, said, recite: O Allah! You are oft forgiving. You like forgiveness. Forgive me as well." (Tirmithi).
The Prophet, peace be upon him, said: "Whoever observe Qiyam (Supererogatory prayer) in the night of Qadr, (Which is in Ramadan), with faith and intention to earn the reward, then all his previous sins are forgiven." (Bukhari and Muslim)
Also, narrated Aisha, may Allah be pleased with her, with the start of the last ten days of Ramadan, the Prophet, peace be upon him, used to tighten his waist-belt (i.e. work hard) and used to offer Salat (prayer) all the night, and used to keep his family awake for the Salat (preyers)" (Bukhari)
In the last ten days of Ramadan, we must work harder more than the last days of Ramadan to get closer to Allah the Almighty and get His forgiveness in this night.