Ibn 'Umar (Allah be pleased with them) reported Allah's Apostle ﷺ as saying: Seek Lailat-ul-Qadr in the last week (of Ramadan).
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ، عُمَرَ - رضى الله عنهما - عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ
" تَحَرَّوْا لَيْلَةَ الْقَدْرِ فِي السَّبْعِ الأَوَاخِرِ " .
• Sahih Muslim, 1165b
• Sahih Muslim, Vol. 3, Book of Fasting, Hadith 2618
• Sahih Muslim, Book of Fasting, Hadith 2618