It is narrated about Hasan that he used to say: The heart of a believer is behind his tongue. So when any of you intends to do something, he should reflect upon it. If it is a matter of goodness, then he should speak about it, and if it is otherwise, then he should remain silent. And the heart of a hypocrite is at the edge of his tongue. So when he intends something, he speaks it out and makes it apparent.