What does sleep represent spiritually?

Do you when away from your body in sleep gain any useful information in spirit?

Yes—at times, the spirit does bring back information—sometimes, in the shape of a warning of coming evil to the individual and impression of the proper course to avoid the evil. Again, there is not the smallest doubt that anyone who is placed in difficult and perplexing circumstances is greatly benefitted by taking what is called a good sleep over it. There is a great truth in that old saying, as there is in many of such sayings. Man is not aware of all the good he might gain by resorting to this simple method in his seasons of perplexity. The fact is that mortals are nearly half their time in the spirit world, that is, if you take into account their thoughtful, contemplative hours along with those devoted to sleep.

―Hafed, Prince of Persia, in Spirit