It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever has three things in him has tasted the sweetness of faith: one to whom nothing is more beloved than Allah; one to whom being burned in fire is more beloved than turning back from his religion; and one who loves for the sake of Allah and hates for the sake of Allah alone."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 720