Imam Ghazali

"Your five senses are like five doors opening on the external world; but, more wonderful than this, our heart has a window that opens on the unseen world of spirit.
In the state of sleep, when the avenues of the senses are dosed, this window is opened, and we receive impressions from the unseen world and sometimes foreshadowings of the future. Our hearts are like a mirror that reflects what is pictured in the Tablet of Fate. But, even in sleep, thoughts of worldly things dull this mirror, so that the impressions it receives are not clear. After death, however, such thoughts vanish, and things are seen in their naked reality."