Deep and inner peace of mind and heart is called "Sakinah" according to the Qur'an. The Qur'an has declared that "Sakinah" descends from the sky on to the hearts of true Mu'mineen (Believers). This shows that true peace of mind is not related in any way to the material things of this world. Therefore, people with lots of wealth and material comforts are not always the happiest people on earth. The poorest people are not always the most unhappy because Allah has not placed success in material things.