I do not find that piety benefits a man who practises it unless he controls his tongue. Certainly, the tongue of a believer is at the back of his heart while the heart of a hypocrite is at the back of his tongue; because when a believer intends to say anything, he thinks it over in his mind. If it is good, he discloses it, but if it is bad he lets it remain concealed. While a hypocrite speaks whatever comes to his tongue, without knowing what is in his favour and what goes against him.