Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 58
Narrated Jundab bin Sufyan:
In one of the holy Battles a finger of Allah's Apostle (got wounded and) bled. He said, "You are just a finger that bled, and what you got is in Allah's Cause."