Narrated Sad bin Abi Waqqas:

I saw Allah's Apostle on the day of the battle of Uhud accompanied by two men fighting on his behalf. They were dressed in white and were fighting as bravely as possible. I had never seen them before, nor did I see them later on.

حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، عَنْ سَعْدِ بْنِ أَبِي وَقَّاصٍ ـ رضى الله عنه ـ قَالَ رَأَيْتُ رَسُولَ اللَّهِ ﷺ يَوْمَ أُحُدٍ، وَمَعَهُ رَجُلاَنِ يُقَاتِلاَنِ عَنْهُ، عَلَيْهِمَا ثِيَابٌ بِيضٌ، كَأَشَدِّ الْقِتَالِ، مَا رَأَيْتُهُمَا قَبْلُ وَلاَ بَعْدُ.