The Prophet (ﷺ) as saying: Seek laitat al-Qadr in the last ten night of Ramadan. When nine (nights) remain (i.e. on the twenty first) , when seven (night) remain (i.e. on the twenty third), and when five (nights) remain (i.e. on the twenty fifth).
Sunan Abi Dawud Book 6, Hadith 11
← Previous Hadith I said to the Messenger of Allah: I have a place in the desert where I live and in which I pray, with the praise of Allah; but give me command about a night when I come to this mosque.

He replied: Come on the twenty third night.

I (a sub-narrator, Muhammad ibn Ibrahim) said to his (Abdullah ibn Unays's) son: How would your father act?

He replied: He used to enter the mosque when he had offered the afternoon prayer, and did not leave it for any purpose till he prayed the morning prayer. Then when he had prayed the morning prayer, he found his riding beast at the door of the mosque, mounted it and got back to his desert.

Sunan Abi Dawud Book 6, Hadith 10 Next Hadith → The Messenger of Allah (ﷺ) used to spend the middle ten days of Ramadan in retirement and devotion (i'tikaf) in the mosque. One year he had retirement and devotion in the mosque (as usual); when the twenty-first night came, and this night when he used to come out his devotion in the mosque, he said: He who has engaged himself in devotion along with me should do so during the last ten days; I saw that night, that was caused to forget it, but I have seen myself prostrating in water and mud on the morning following (that night), so seek it in the last ten days and seek it every night with an odd number. Abu sa'id said: Rain fell that night, the mosque that was thatched building dripped, and my eyes saw the Messenger of Allah (ﷺ) with the traces of water and mud, on his forehead on the morning following the twenty-first night.

Sunan Abi Dawud Book 6, Hadith 12