Muwatta Imam Malik Book of I'tikaf in Ramadan, Hadith 11
Ziyad related to me from Malik from Hisham ibn Urwa from his father that the Messenger of Allah ﷺ said, "Search for Laylat al-Qadr in the last ten days of Ramadan."
وَحَدَّثَنِي زِيَادٌ، عَنْ مَالِكٍ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ " تَحَرَّوْا لَيْلَةَ الْقَدْرِ فِي الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ " .