Allah - the Most High - said
"The Believers are only those who, when Allah is mentioned, feel a fear in the hearts, and when His Verses are recited to them, it increases their eemaan (faith), and they put their trust and rely upon Allah alone. They are those who perform the Prayer and spend out of that which We have given them, they are Believers in truth. For them are grades of dignity and nobility with their Lord, and also forgiveness and generous provisions." [Soorah al-Anfaal 82-4]