It has been narrated on the authority of Jundub b. Sufyan who said:A finger of the Messenger of Allah (ﷺ) was wounded in one of the encounters He said: Thou art just a little finger which has bled, and what thou hast experienced is in the cause of Allah.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، وَقُتَيْبَةُ بْنُ سَعِيدٍ، كِلاَهُمَا عَنْ أَبِي عَوَانَةَ، قَالَ يَحْيَى أَخْبَرَنَا أَبُو عَوَانَةَ، عَنِ الأَسْوَدِ بْنِ قَيْسٍ، عَنْ جُنْدُبِ بْنِ سُفْيَانَ، قَالَ دَمِيَتْ إِصْبَعُ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي بَعْضِ تِلْكَ الْمَشَاهِدِ فَقَالَ " هَلْ أَنْتِ إِلاَّ إِصْبَعٌ دَمِيتِ وَفِي سَبِيلِ اللَّهِ مَا لَقِيتِ " .
Muslim
The Book ofJihadand Expeditions • Hadith 136