Sunan Abi Dawud 1386
سنن أبي داود#1386Sahihحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، أَخْبَرَنَا شُعْبَةُ، عَنْ قَتَادَةَ، أَنَّهُ سَمِعَ مُطَرِّفًا، عَنْ مُعَاوِيَةَ بْنِ أَبِي سُفْيَانَ، عَنِ النَّبِيِّ صلى الله عليه وسلم فِي لَيْلَةِ الْقَدْرِ قَالَ " لَيْلَةُ الْقَدْرِ لَيْلَةُ سَبْعٍ وَعِشْرِينَ " .
Narrated Mu'awiyah b. Abi Sufyan :The Prophet (ﷺ) as saying: Lailat al-qadr is the twenty-seventh night (of Ramadan)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiIsnaad Hasan
In-book reference: 6:16