Sunan an-Nasa'i 549
سنن النسائي#549Sahihأَخْبَرَنِي إِبْرَاهِيمُ بْنُ يَعْقُوبَ، قَالَ حَدَّثَنَا ابْنُ أَبِي مَرْيَمَ، قَالَ أَخْبَرَنَا أَبُو غَسَّانَ، قَالَ حَدَّثَنِي زَيْدُ بْنُ أَسْلَمَ، عَنْ عَاصِمِ بْنِ عُمَرَ بْنِ قَتَادَةَ، عَنْ مَحْمُودِ بْنِ لَبِيدٍ، عَنْ رِجَالٍ، مِنْ قَوْمِهِ مِنَ الأَنْصَارِ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَا أَسْفَرْتُمْ بِالْفَجْرِ فَإِنَّهُ أَعْظَمُ بِالأَجْرِ " .
It was narrated from Mahmud bin Labid, from some men among his people who were of the Ansar, that the Messenger of Allah (ﷺ) said:"The more you delay Fajr, the greater the reward
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:
In-book reference: 6:56