Sahih Muslim | Book 1 | Chapter 16

Narrated by Anas
It is reported on the authority of Anas that the Prophet of Allah (may peace and blessings be upon him) said: There are three qualities for which anyone who is characterised by them will relish the sweetness of faith: he to whom Allah and His Messenger are dearer than all else; he who loves a man for Allah's sake alone; and he who has as great an abhorrence of returning to unbelief after Allah has rescued him from it as he has of being cast into Hell.

Narrated by Anas
It is reported on the authority of Anas that the Messenger of Allah (may peace be upon him) said: There are three qualities for which any one who is characterised by them will relish the savour of faith: that he loves man and he does not love him but for Allah's sake alone; he is to whom Allah and His Messenger are dearer than all else; he who prefers to be thrown into fire than to return to unbelief after Allah has rescued him out of it.

Narrated by Anas
A similar hadith has been reported on the authority of Anas (with another chain of transmitters) with the exception of these words: that he again becomes a Jew or a Christian.