Jami` at-Tirmidhi Book 47, Hadith 404
A man said to the Prophet: “O best of creatures!” So he said: “That is Ibrahim.”
“I said to Ubayy bin Ka’b: ‘Your brother Abdullah bin Mas’ud says: “Whoever stands (in voluntary prayer) the whole year, then he will have reached the Night of Al-Qadr.’” So he said: ‘May Allah forgive Abu Abdur-Rahman. He knows that is during the last ten (nights) of Ramadan, and that it is the night of the twenty-seventh. But he wanted the people to not rely upon that.’ Then he uttered an oath, that without exception it is on the night of the twenty-seventh.” He said: “I said to him: ‘Why is it that you say that O Abu Al-Mindhir?’ He said: “By the sign or indication which the Messenger of Allah informed us of: ‘That the sun rises on that day having no beams with it.’”
“The Messenger of Allah recited this Ayah: ‘That Day it will declare its information.’ He said: “Do you know what its information is?” They said: “Allah and His Messenger know better.” He said: “That it testifies about what every male or female slave (of Allah) did upon its surface. It says: ‘He did this and that on this day.’ This is its information.”