Excessive Concern for Bodily Cleanliness Whilst Being Neglectful of Cleanliness of the Heart and Mind
A person who expends his precious time in only istinja, washing the hands, mouth and feet, bathing, ensuring that his dress and appearance are clean and tidy and looking for running water without concern for the purification of his inside (his heart and mind), such a person is gripped by whispers from Shaitaan and is afflicted with the sickness of melancholia – a depressive state.
Bodily cleanliness has been established to indicate the cleanliness of the heart and mind. Washing the face, hands and feet is to move the heart.
All our outward statements and actions, all our activities and states of inactivity certainly effect our hearts.
Or put it this way: Whatever is embedded within us is reflected by the mirror of our outward actions. But this does not mean that external purification is not necessary. It simply means that together with cleaning the outward body, cleaning the inside (the heart and mind) is also necessary.
(Al-Masaalihul Aqliyyah)