It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "There are three things; whoever has them finds the sweetness of faith: that Allah and His Messenger are dearer to him than everything else; that he loves a person only for the sake of Allah; and that, once Allah has saved him from disbelief, he hates to return to it just as he hates to be thrown into the Fire."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7988