“Tests are shown to the hearts like a straw mat, straw by straw. Whichever
heart accepts them, and absorbs them, gets a black spot placed on it, and
whichever heart rejects them, gets a white, clear spot on it. This goes on until
the hearts are of two types: a heart which is white, smooth, and clear like a
polished stone which will not be harmed by further trials or tests for as long
as the heavens and the earth last, and another dark and blemished; it is like
a hook turned over the wrong way on which nothing can be hung – it neither
acknowledges what is right nor rejects what is wrong, except for that which
happens to coincide with its lusts and inclinations with which this heart has
become fully absorbed.”


(Bukhari & Muslim)