Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) reports that the Messenger of Allah (peace and blessings be upon him) said: "Hearts are of four kinds: (1) A bare heart which has no covering on it, it is bright like a lamp, and this is the heart of the believer; its lamp is its light within it. (2) A heart that is covered, upon which its covering is tied, and this is the heart of the disbeliever. (3) An inverted and upside-down heart, and this is the heart of the hypocrite who knowingly rejects. (4) A heart that is expanded, this is the heart in which there is both faith and hypocrisy; the example of faith in it is like a plant which is nourished by good water, and the example of hypocrisy in it is like a wound which is increased by pus and blood. So whichever of the two dominates over it, it overpowers the other."