Sunan Abi Dawud 2757
سنن أبي داود#2757Sahihحَدَّثَنَا مُحَمَّدُ بْنُ الصَّبَّاحِ الْبَزَّازُ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ أَبِي الزِّنَادِ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّمَا الإِمَامُ جُنَّةٌ يُقَاتَلُ بِهِ " .
Abu Hurarirah reported the Apostle of Allaah(ﷺ) as saying “A Muslim ruler is shield by which a battle is fought.”
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: 15:281