Ibn Shihab relates that among the Ansar, then of Banu al-Harith bin al-Khazraj, who were martyred on the day of Uhud, the name of Sayyiduna Sa'd bin Suwayd (may Allah be pleased with him) is included.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5453