The Book of the Merits of the Companions
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ الرُّزِّيُّ، حَدَّثَنَا عَبْدُ الْوَهَّابِ بْنُ عَطَاءٍ الْخَفَّافُ، عَنْ سَعِيدٍ، عَنْ قَتَادَةَ، حَدَّثَنَا أَنَسُ بْنُ مَالِكٍ، أَنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم قَالَ وَجِنَازَتُهُ مَوْضُوعَةٌ - يَعْنِي سَعْدًا - " اهْتَزَّ لَهَا عَرْشُ الرَّحْمَنِ " .Anas b. Malik reported Allah's Messenger (ﷺ) as say- ing:That his bier (that of Sa'd) was placed (before them) and the Throne of the most Compassionate shook
From Sahih Muslim, whose reports the scholars accept as authentic.