Musannaf Ibn Abi Shayba 23:96

Abu Mu'awiyah narrated to us, from al-A'mash, from 'Amr ibn Murrah, from Abu al-Bakhtari, from Hudhayfah, who said: The hearts are four: A heart that is overturned, and that is the heart of the hypocrite. A heart that is wrapped, and that is the heart of the disbeliever. A heart that is smooth, as if there is a lamp in it that shines, and that is the heart of the believer. And a heart in which there is hypocrisy and faith; its likeness is like a sore that is supplied by pus and blood, and its likeness is like a tree that is watered by good water, so whichever of the two prevails, it prevails over it.