Sahih al-Bukhari, Book 56, Hadith 19 (In-Book) ⓘ
Narrated Jundab bin Sufyan: In one of the holy Battles a finger of Allah's Messenger (got wounded and) bled. He said, "You are just a finger that bled, and what you got is in Allah's Cause."
حَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا أَبُو عَوَانَةَ، عَنِ الأَسْوَدِ بْنِ قَيْسٍ، عَنْ جُنْدُبِ بْنِ سُفْيَانَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ فِي بَعْضِ الْمَشَاهِدِ وَقَدْ دَمِيَتْ إِصْبَعُهُ، فَقَالَ " هَلْ أَنْتِ إِلاَّ إِصْبَعٌ دَمِيتِ، وَفِي سَبِيلِ اللَّهِ مَا لَقِيتِ " .
also referenced under: Hadith 2802 (DarusSalam) & Volume 4, Book 52, Hadith 58 (USC-MSA)