Sahih Bukhari
Fighting for the Cause of Allah (Jihaad)
Volume: 004 / Book Number: 052 / Hadith Number: 51
Narrated Abu Huraira:
The Prophet said, "A place in Paradise as small as a bow is better than all that on which the sun rises and sets (i.e. all the world)." He also said, "A single endeavor in Allah's Cause in the afternoon or in the forenoon is better than all that on which the sun rises and sets."