عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ قَالَ لَقَدْ رَأَيْتُ عَنْ يَمِينِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَعَنْ يَسَارِهِ يَوْمَ أُحُدٍ رَجُلَيْنِ عَلَيْهِمَا ثِيَابٌ بِيضٌ يُقَاتِلَانِ عَنْهُ كَأَشَدِّ الْقِتَالِ مَا رَأَيْتُهُمَا قَبْلُ وَلَا بَعْدُ
It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him), he says: On the day of Uhud, I saw two men on the right and left of the Messenger of Allah (peace and blessings be upon him), they were dressed in white clothes, they were vigorously defending him. I had never seen them before nor after that.