Sahih Bukhari
Ablutions (Wudu)
Volume: 001 / Book Number: 004 / Hadith Number: 238
Narrated Abu Huraira:
The Prophet said, "A wound which a Muslim receives in Allah's cause will appear on the Day of Resurrection as it was at the time of infliction; blood will be flowing from the wound and its color will be that of the blood but will smell like musk."