The true Muslim believes in the angels of God, They are purely spiritual and splendid beings whose nature requires no food or drink or sleep. They have no physical desires of any kind nor material needs. They spend their days and nights, in the service of God. There are many of them, and each one is charged with a certain duty. If we cannot see the angels with out naked eyes, it does not necessarily deny their actual existence, There are many things in the world that are invisible to the eye or inaccessible to the senses, and yet we do believe in their existence. There are places we have never seen and things like gas and ether that we could not see with our naked eyes, smell or touch or taste or hear; yet we do acknowledge their existence. Belief in the angels originates from the Islamic principle that knowledge and truth are not entirely confined to the sensory knowledge or sensory perception alone,(16:49-50; 21:19-20. see also the references in article two above).