The Book of Fasting
13/40. Chapter:
The virtue of Lailat Al-Qadr and the Exhortation to seek it; When it is and the most likely times to seek it
Sahih Muslim
وَحَدَّثَنِي عَمْرٌو النَّاقِدُ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالَ زُهَيْرٌ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، - رضى الله عنه - قَالَ رَأَى رَجُلٌ أَنَّ لَيْلَةَ الْقَدْرِ لَيْلَةُ سَبْعٍ وَعِشْرِينَ . فَقَالَ النَّبِيُّ صلى الله عليه وسلم " أَرَى رُؤْيَاكُمْ فِي الْعَشْرِ الأَوَاخِرِ فَاطْلُبُوهَا فِي الْوِتْرِ مِنْهَا " .
Salim reported on the authority of his father that a person saw Lailat-ul- Qadr on the 27th (of Ramadan). Thereupon Allah's Apostle (ﷺ) said: I see that your dreams agree regarding the last ten (nights of Ramadan). So seek it on an odd number (of these ten nights).
Reference : Sahih Muslim 1165cIn-book reference : Book 13, Hadith 269USC-MSA web (English) reference : Book 6, Hadith 2619