Jihad: The forgotten obligation
31: Purchasing Weapons for Jihaad
Narrated Umar (ra), the properties of Bani an-Nadhr which Allah had transferred to his Apostle (saw) as booty were not gained by the Muslims with their horses and camels. The properties therefore, belonged especially to Allah's Apostle (saw), who used to give his family their yearly expenditure and spend what remained thereof on arms and horses, to be used in Allah's path (jihaad). (Sahih Bukhari, p.407, vol.1)