Sahih Bukhari
Belief
Volume: 001 / Book Number: 002 / Hadith Number: 15
The Prophet said, "Whoever possesses the following three qualities will have the sweetness (delight) of faith: 1. The one to whom Allah and His Apostle becomes dearer than anything else. 2. Who loves a person and he loves him only for Allah's sake. 3. Who hates to revert to Atheism (disbelief) as he hates to be thrown into the fire."