وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، عَنْ عُقْبَةَ، - وَهُوَ ابْنُ حُرَيْثٍ - قَالَ سَمِعْتُ ابْنَ عُمَرَ، - رضى الله عنهما - يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ الْتَمِسُوهَا فِي الْعَشْرِ الأَوَاخِرِ - يَعْنِي لَيْلَةَ الْقَدْرِ - فَإِنْ ضَعُفَ أَحَدُكُمْ أَوْ عَجَزَ فَلاَ يُغْلَبَنَّ عَلَى السَّبْعِ الْبَوَاقِي ‏"‏ ‏.‏

Ibn Umar (Allah be pleased with them) reported Allah's Messenger (PBUH) as saying: Seek it (Lailat-ul-Qadr) in the last (ten nights). If one among you shows slackness and weakness (in the earlier part of Ramadan), it should not be allowed to prevail upon him in the last week. Translation Not Available

Book Ref: Sahih Muslim Book 13 Hadith 2621
Web Ref:  Sahih Muslim Book 6 Hadith 1165 e